AFAIK most of them are barely active with few users. I think the reason as to why there’s so many is because anyone can make a community without there being much bureaucracy involved as long as it obeys the rules.

Admins are quite tolerant: there’s even a “Trotskyism” community (the last post being from two months ago about why the community exists) despite Lemmygrad being quite explicitly Marxist-Leninist. There aren’t many Marxists from other tendencies because they kinda just choose not to come here as opposed to us actively suppressing them, but anyways I digress.