We can't review the history of the alt-right without mentioning the online message board 4chan, infamous for being racist and anti-Semitic and every other thing it is bad to be. 4chan's trajectory is a another great mystery. In 2010, geeky extremely-online young people were almost universally liberal democrats. Racism was associated with elderly white Southerners who would presumably die off in a few years anyway. 4chan had no connection to them or any other historical racist tradition. It was annoying and trolled people a lot, but that was it. Its conversion to full-on bigotry was unexpected, at least by me. It would be like if you woke up one day and everyone on Twitter was a Pol Pot supporter.

I think they irony-ed themselves so hard that they accidentally ended up as Nazis. You could always go to 4chan and find people saying horrible racist things ironically. That was the whole point of the anonymous message board - people would troll each other by saying the most awful thing they could think of, and whoever took it seriously first lost. Last I heard from them they were trying to use meme magic to make the coronavirus kill as many people as possible. This is impossible to take seriously, and for a long time their racism was the same way - a lot of the supposedly anti-Semitic posts bore obvious fingerprints of having been written by Jews who were having a fun time laughing at themselves. But if you're in a community where everybody puts a lot of effort into pretending to be pro-racist all the time, and where any breaking of kayfabe gets punished, eventually some people who aren't in on the joke just get actually racist, and if you're so devoted to edginess that you can't politely take those people aside and explain, eventually that takes over the culture. I know this is a weird theory, but Kurt Vonnegut was a smart guy and he said "Be careful who you pretend to be, because you are who you pretend to be".