Nerd or geek culture was quite reactionary for a long time now. It's a product of the (predominantly white male) western bourgeoisie and labour aristocrats, and its links to racism and sexism go quite deep.

This 3-page article (page 1, page 2, page 3) does a good job at analyzing these cultural aspects. It's a very interesting read.

Here's an excerpt from the introduction:

As geekdom moves from the cultural fringes into the mainstream, it becomes increasingly difficult for the figure of the geek to maintain the outsider victim status that made him such a sympathetic figure in the first place. Confronted with his cultural centrality and white, masculine privilege—geeks are most frequently represented as white males—the geek seeks a simulated victimhood and even simulated ethnicity in order to justify his existence as a protagonist in a world where an unmarked straight white male protagonist is increasingly passé.

Our investigation proceeds through three core concepts / tropes prevalent in geek-centered visual narratives:

1. "geek melodrama" as a means of rendering geek protagonists sympathetically,
2. white male "geek rage" against women and ethnic minorities for receiving preferential treatment from society, which relates to the geek’s often raced, usually misogynistic implications for contemporary constructions of masculinity, and
3. "simulated ethnicity," our term for how geeks read their sub-cultural identity as a sign of markedness or as a put-upon status equivalent to the markedness of a marginalized identity such as that of a person of color.

We analyze these tropes via an historical survey of some key moments in the rise of geek media dominance: the early-20th century origins of geekdom and its rise as an identifiable subculture in the 1960s, the mainstreaming of geek masculinity in the 1970s and 80s via blockbuster cinema and superhero comics, and the postmodern permutations of geekdom popularized by Generation X cultural producers, including geek/slacker duos in “indie” cinema and alternative comics.

gamergate (2014) was unironically the mainstream debut of the alt-right.

I wouldn't say that it has? At least not unilaterally.

I'd lay the blame squarely on capital's doorstep. Capital runs most major internet forums, and capital decides which views are platformed and which are muted. Fascism and capital go hand in hand. Rage gets more clicks, which means more ad revenue.

We're both on sites loaded with nerds who are comrades. Nerds are not at all inherently fascist. The terminally online are not inherently fascist. However, "Internet/Nerd culture" was doomed to become fascist when it became a packaged commodity. The most successful "nerds" were also the most ruthlessly capitalist. Wozniak vs Jobs and all that.

Inceldom also has a part to play in this, but, again, this is largely a product of capital. They're useful idiots. Like LBJ put it, "If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you." Lonely men are convinced women are to blame, that women are garbage, and they become clients and, frankly, weapons. There are a lot of lonely nerds out there thanks to the isolation that capitalism encourages.

You say this change happened in the mid-2010s; putting that in context, social media as we know it really only started taking off in the late oughts. Reddit and Facebook were like 2005-ish, and didn't hit their strides for a few years. Facebook's IPO was 2012. Capital.

And, finally, nobody's immune to propaganda. It's not just "nerd culture" that's taken this turn, it's a society-wide poison.

Incels and women hating are and will lead one farther down the road of reactionary beliefs

Your framing and your questions seem to mash many different things—spanning decades—together as if it was all one thing. I’m not going to try to disentangle it all, but I’ll make a few of observations.

• The Internet is a product of the US’s military-industrial complex.
• “Apolitical” isn’t. “Apolitical” is the politics of maintaining the status quo. It’s the politics of I Just Wanna Grill for God's Sake: White American male labor aristocrats.
• To a large extent New Atheism was a racist, Islamophobic reaction to 9/11, which provided ideological support for the imperial core’s War On Terror.

Selection bias, I think. It depends on the site you're using, but often communities are dominated by people who can afford to spend enormous amounts of time on the internet. That's going to favor people with money and free time, not to mention the people who are literally paid to post.

Nerd culture was always fairly reactionary, all things considered. The "girls don't play video games" trope was so overplayed in the mid 00's even Ctrl+Alt+Del was able to subvert it by having a gamer gf and B^U is not a creative person by any stretch of the word.

Although it did get worse when reactionaries realised they could make money by criticizing otherwise non-issues. If San Andreas came out today the right wing youtubers would lose their minds that the protagonist is black, the main antagonist is a cop and the secondary antagonist is a CIA agent and the supporting cast includes a female Latina, a weed smoking hippy and a disabled Chinese American. Gamergate's consequences hasn't exactly fallen away.

Steve Bannon

Internet was initially only accessible by military and academia, its never not been reactionary

Subcultures are always more extreme expressions of an aspect/aspects of their supercultures.

Internet and geek cultures both, in the Anglosphere, have always been proponents of American Exceptionalism and Liberal Exceptionalism. And both of those things have progressed to fascism.

I'm gonna introspect here. Most of the other explanations in this thread I agree with, but I'm gonna focus inwards on the left.

The left abandoned geek culture spaces and allowed chuddery to take root unimpeded. We have a tendency to leave spaces to create our own instead of fighting over them. There are pros and cons to this, but one clear con imo is that we forfeit any culture wars before they're even fought. Sure, we also get banned and whatnot, but we don't (for example) use this place to coordinate raids on ! mainstream spaces the way 4chan and like do.

I also think there was a general distain for geek culture as a hyper capitalist expression of the lumpenproletariat. To what extent that is true is up for debate imo. There are still many anti-capitalist expressions from gamers and the like, but there are not enough leftist voices to frame them as such inside those communities. Recently we've had some discussions here about how abandoning and looking down on the rural working poor (so called "rednecks") and I think that's a really apt comparison.

The far right put in the work and ideological effort to fight over gamers and geeks, the left did not. As other comrades here have pointed out, any space without a leftist presence automatically drifts right.

I'm truly convinced that a huge part of this was moot leaving 4chan in 2015. Nerd culture has always been misogynistic and insular, but it never seemed politically focused until the past 10 years. It used to be more unfocused horribleness. When moot resigned from 4chan, there was a genuine white supremacist plot to gain moderator positions and push fascist rhetoric. It worked. All that ambient horribleness became laser focused and more coherent.

Also probably a lot more to do with material conditions honestly. The fraying economic features of the 2008 recession were never truly fixed. People no longer believe in a future and it became harder for nerd culture to act as an escape. Everyone's more stressed, more pissed off, and more vocal. With nerd culture the ambient feelings got pushed forward as the things themselves ceased being enough of a draw on their own. More frayed and deranged types started demanding their misogynist, white supremacy be reinforced more aggressively, in every moment, by all media.

So, the nerd culture of pre-gamergate had a big streak of the internet atheist movement. I'm not actually sure you could meaningfully say one was separate from the other. An unspoken part of that was libertarianism. Real end-of-history hours. That's not to say there weren't non-libertarians in that space, it's just the default was you were assumed to be white, male, libertarian, and into pop-culture franchises above and beyond ordinary consumptive habits of the general public.

A big part of nerd-dom, promoted by the owners of these franchises themselves, was the competitive consumption of cultural artifacts. The most obvious manifestation of this is large walls of collectibles, pristine in their packaging, which requires a decent amount of disposable income to indulge in. You didn't have to spend lots of money, of course. You could competitively consume "lore", which is often free from your local library.

The consumptive practices excluding certain income levels, the hierarchical nature of "who was in", and the end of history I think explains a lot of reactionary nerds today (even though nerdy stuff has been used to explore emancipatory ideas about queerness, different societies etc... The artists tend to be more woke than the fans/fan leaders).

There is also the idea of scholarly merit and social exclusion. Obviously its a stereotype, but people who lived that (or believe they lived that) became part of the tech start up culture that drove a lot of the wealth in the Anglosphere, especially as decent paid industrial work started to decline. Again, the increase in wealth lends itself to walls of arcade games and reactionary content.

Politics has always been present in the works and in the fan culture, but there was a certain tendency across everything in the 90s and 2000s to think of itself as apolitical and non-ideological.

Nowadays, enough traditional nerds have enough money and clout to direct movie franchises. No longer is it business majors dictating that "audiences wouldn't understand a lore accurate X-Men movie" or whatever. But the economics of it are the same (or similar).

Back in the 90s some nazi groups invested 10k in internet propaganda, I figure the internet being so fascistic is just the results of that along with nerds being all sorts of fascistic is just a product of western academia culture to an extent as well.

Nerd culture was targeted by companies seeking a profit from that market.

It also became way less underground and way more pop as a result.

This allowed a lot more libs in, killing any potential left approach

Back in 2009, the unfortunate precipitation of the infamous Endless Eight arc caused many 4chan posters to abandon Haruhiism and drift afloat in a position of moral vulnerability which the Nazis quickly moved to exploit

Nerd culture saw itself as white (or certain east-asian), male, middle class plus and in the developed world. It was bound to devolve into reactionary thought. The only pro I see is its tendency to be accepting or at least ambivalent towards transpeople, even 4chan (outside of /pol/) seems to be more accepting towards trans than their political opinions of everything else.

Enough people got online to ask the original nerds to stop calling women femoids and rather than adapt they reflexively doubled down.

Rinse and repeat for 10 years.

Interesting that you mention that, I think I talked about that one time. Basically last decade was the best until early 2017, I mean the internet, movies, games, vibe, everything, it was like early-mid 1980s for our parents and older people. Most of the popular trash today was non existent and Reddit was a lot less popular.

Then exactly like you said, it went to shit in 2017, social media became cancer with all the political shit they started, for example, on Balkan YouTube during 2012-2016/early 2017 times there were very good YouTubers making content for little kids, older kids and adults alike, playing games, especially Minecraft, GTA V and horror games, videos about tech, work out, funny sketches, Creepypasta channels etc. After that came idiots who were fighting among themselves and causing political and regular dramas because that became popular for some reason, and of course sexual content and fighting over bullshit became normalized among them.

I can't even wrap my head around YouTube recommendations: shitting on movies, complaining about ''politics'' in them(''politics'' being women and minorities) big games being hyped and then rushed, then videos about complaining 24/7 about them, milking and shitting on OGs with countless pointless sequels and unnecessary updates, you name it. Cringe stuff on social media, people complaining about everything, cancel culture, Twitter, not to mention openly nazi nuts in the comments somehow passing unpunished.

I don't really know what exactly caused this.

It's a violent (over)reaction to 2013-2016 SJW culture. Now hating women and minorities makes you "based" and not a weirdo.