That racist video Enzo Fernández posted played a part in that.

It grew out of Black Twitter, Black Youtube and more prominently Black TikTok as a consequence of the explosion of racist content concerning Black players on FIFA teams

It didn't start there though, other latin americans were already doing that on social media way before that.

It gained viral motion because of the factoid concerning Argentina genociding all its Black people and because of viral racist actions made by Argentina fans, also the fact there are no Black players on Messi's team, the fact Trump gave them 20 billion dollars, the blatant favoritism displayed by the refs, the fact Argentinians were waving Israeli flags.....

Yes. Though it wasn't just genociding all the black people as in they just killed them, after the 1860s and the fall of Juan Manuel de Rosas and the fall of the Federalists, the Unitarians inspired by the USA and Europe, actively erased the history, culture and contribution of Native Americans, Afro-Argentinians and Women from the country's history (same thing happened in Brazil and Uruguay).

They also did a bunch of revisionism to make the country's first leaders way more racist than what they actually were (Argentina was initially supposed to be a Monarchy ruled by Native Americans, but the rich white buenos aires elite sabotaged that). Most Afro-Argentinians left the country for Brazil or other South American nations due to how bad the Unitarians made the whole country, just a few of them remained (around less than 1%, though it debatable how much people are descedent of Afro-Argentinians but won't admit it).

Theres still a lot of refusal by even some leftists in Argentina (and tbh all of LatAm) to talk about this. Yes, LatAm is not as racist as the USA (we never had segregation for example) but some people just refuse to accept how we still have racism here. At least in more recent years people have been recognizing the contribution of Natives Americans and Afro-Latinos in out culture and history.

I mean if Argentina was dedicated to generating an organic hate campaign against itself using the World Cup, they did everything possible to make it happen

It was mostly organic IMO. But some Americans were actively attacking not just Argentinians but also Latin Americans as if we're just one country (???), honestly is pretty dumb and some people who know nothing about LatAm were sayings stuff that doesn't even make sense because they don't understand our history or how culture is here (also a bunch of asshole gusanos were being racist but thats expected from them, they think if they bootlick white people they'll be consider white).