Part of the appeal of these ideologies is clearly that they are offensive, not permitted on mainstream platforms, and therefore are something that their participants can "own" and that won't be co-opted by consumerism.
It's the same thing that fueled "Satanic" rock and similar things. Fascism is devil music. That most people are offended by it and mainstream authorities preach against it is a huge part of its appeal.
Elon Musk might be damaging this a little. It's hard to think you're a rebellious counterculture when you have one of the world's richest men acting as a public torch bearer.