At the risk of getting put on horse-watch, I'm going to strongly agree with you about

or if they're a redditor they start talking about Muslims

I lurked on /r/atheism a long time ago while grappling with the fallout from my faith shattering, and what I concluded was that that crowd of "new atheists" were racist as hell. If I talked about not being muslim anymore because I wanted God to actually exercise power to make the world better, and since that doesn't happen I can't believe in anything supernatural anymore: Upvotes galore, sympathetic comments, people commiserating and trying to help me cope. If I said that bombing Muslims because you think their governments are too theocratic / autocratic is a horrible way to "liberate" anyone, and anyway people didn't need to be "liberated" by force, they just needed to be socially free to choose their beliefs and lifestyles (and, when free to choose, most people would remain Muslim because it's not actually bad to be religious, and you can be gay and trans and progressive and still be religious): Downvoted to hell and people dogpiling me and even citing the Quran out of context to tell me, someone raised in Islam, that I didn't know shit about it. If I pointed out that it's absolutely ridiculous for a mostly white mostly western userbase to talk so much shit about Islam at all when evangelical christianity is the thing that's actually threatening people's civil liberties: "terrorism", "migrants invading europe and making the crime rate skyrocket" (gee, why would a bunch of refugees suddenly show up? Did western foreign policy have anything to do with that?), and even worse things I don't want to retype out because it's so hateful.

The heel turn that Richard Dawkins took was not a surprise. That motherfucker ended up deciding he was a secular christian because he was so bothered by seeing Muslim women wearing clothes.

Redditors as a group seem to just hate Muslims because redditors are western chauvinists. That's the real reason they don't complain about committing a livestreamed holocaust on our western goverenments' dime. They like seeing people being murdered, as long as they're the right religion.

a lot of these people, and in most communities dominated by westerners in general, is that they retain a lot of their chauvinism, especially the yanks. they would shout for the destruction of the settler state for israel while praising fucking new york city in the next post. the discontinuity between how they treat the two settler states is something i've repeated numerous times.

Leftypol is extremely reactionary. I'm also suspicious of anyone who uses it because they don't have rules like actual leftist spaces against bigotry and slurs.

I only browse 4chan for opposition research to understand and recognize dogwhistles. It's one of the reasons I no longer debate conservatives elsewhere because it's clear mainstream reactionaries have absorbed the Alt-Right into their platforms. This includes 4chan-style """trolling""" where they pretend like they were "just joking" if you call out their shitty beliefs.

The place was ground zero for online neo-nazis recruited by Steve Bannon outside of actual Stormfront.

they use abbreviations and slurs no one knows.

Exactly 💯%. They'll carry over their reactionary thinking and hope anyone won't notice.

whenever a leftist ik admits they used or use tumblr/4chan/reddit regularly

What you say is valid but it's also not like there's platforms you'd expect a person IRL to be on that are better than those?