I believe Steven Pinker has a point about how people end up on the white ethno state alt-right kick. (Leadbelly posted the video pages back.)
Basically, they haven't developed the critical thinking tools or the care for nuance that is needed to defend an open mind from bad ideas. They then see lies from group X and see a fact from group Y and become overly accepting of group Y. They are still fanatics, but they just switched sides. This is also how you get Social Studies Warriors. That sort of group is full of people who very mean and rude to gay people or black people in the past, then has a "wokening" or whatever and... remains incredibly mean and rude to people but have found out which targets they can get away with abusing. They were once asshole bros, now they're asshole cucks, never learning the asshole part was the problem.
AntiFa and Alt right groups, they specifically target lost, directionless youth. They give them a false ideal of order or a bad cause dressed up as a good one., Those groups are full of people who haven't' developed mental survival mechanisms.