I dont know how to convey this in a sticky way but these extremist beliefs are not organic. People do not organically become neo nazis or Marxist lennists. They are not randomly adopting these beliefs because of circumstances of the world.

These groups specifically target and craft messages and strategies. You can see it if you browse their spaces and they openly talk about it. They will have threads where they pick a common argument and refine the response. They then go into the space and make the bad side of the argument on one account and pile on it with the refined arguments. Praise all the people that agree as intelligent and demean all the people that disagree. It really does not take that many people to successfully flip a space.

Because the message is crafted its always just on the edge of what can be banned for. If they are banned its a good opportunity to act like it was a massive overreach.

People see these tiny little seeds getting planted and eventually when they are presented with the argument they reach the extreme position and feel like it was their own work.