If you care about downvotes, then I could see your point about the Fediverse being hostile to some more mainstream opinions. I’ve made some pretty vanilla comments about markets/politics that have gotten downvoted for not being left-wing, but I don’t really care about that.
I’ve never been called a “nazi”, but I don’t go out of my way to antagonize anyone and try to add to the conversation and if my reply is something along the lines of “socialism sucks and you suck” then I don’t post it.
I think what it comes down to though is that the fediverse experience requires some curation and restraint compared to other larger platforms where you can go pretty much unoticed and can pretty much always find a group of people of similarly ideologically minds