It’s also how flat earthers started. 4chan started satirically memeing about flat earth. Then idiots saw it, missed the satire, and picked it up as a serious thing. At that point, 4chan went “this is funnier than any satire we could make” and stood back to watch the crazies launch rockets into the upper atmosphere.
Flat earthers have been around (heh) for centuries. It's mostly a religious thing in order to rebuke science in order to keep people stupid. There's a passage in the bible that refrences the four corners of the earth that gets refrenced by these people as proof. It's a way to keep people in their cult, because the outsiders are the ones who are tricked into beleiving in round earth ftom scientists.
I would say that it really became a thing in its current form in the 1800s. Lots of the weird Biblical “literalism” (and I think things like Salafism/Wahhabism) come from the combination of widespread literacy and direct access to the texts + those ideologies that deny that you need anything outside the text to interpret them yourself/solo scriptura.
What we’re seeing now is related to shitposting being taken seriously for sure (the “birds aren’t real” thing has also been making a slow shift from stupid joke to conspiracy therapy, I think that’s how “Helen Keller” don’t real started)
I trace it back a bit further than 4chan though. You start to see it all the way back in the 90s on Usenet, pretty sure that’s around when the Flat Earth Society Forums - which were clearly mostly Poes - started too.
My dad used to be on 4Chan all the time in the 2000s, he told me being called a fag was considered a form of endearment, not an insult. I've never heard newfag or oldfag be used by the far right, they typically go for actual insults instead.
"fag" is a homophobic slur that was actually even more hurtful to use back in the early 2000s when LGBT people were a lot less accepted by society than today. That said your Dad is technically correct and it was a "term of endearment" among homophobes on 4chan which was largely comprised of straight white men in college had/has a self-deprecating sense of humor.
4chan's downfall was mainstream media telling everyone that Nazis were on the site, so all the Nazis who were watching mainstream media went to 4chan and without moot running it, they were allowed to fester.