The Fediverse is home to a lot of young, tech-minded people distrustful of major corporations. The younger generations are more likely to come out as transgender due to greater awareness and acceptance of gender identity and dysphoria, and a decentralised, open platform is naturally going to appeal to communists, syndicalists and other left-wingers who don't want some billionaire buying the next website they get comfortable on. And funnily enough, there are a surprising number of trans people in the tech sector, to the point where trans-flag socks have become a meme among programmers.

This seems like the most straightforward answer. But it doesn’t explain why people on the right haven’t come to the fediverse in proportional numbers. I know a lot of right leaning Libertarian communities, and for some reason they like cryptocurrency and FOSS but not the fediverse.

There are right-wing instances of Mastodon (gab, truth, and others), not to mention many Pleroma ones, as well as Lemmy (exploding heads, and probably others). It’s just that they get quickly defederated by everyone else for various valid reasons (usually hate and abuse, sometimes even child porn), so you don’t get to interact with them much. They just get stuck in their own bubble.