@GuyDudeman (Taking other people off the list so their mentions don't get flooded.)
When I say "hostile", I mean all of the above! Mastodon's decentralization has counter-intuitive effects, after one is used to what happens on more centralized platforms.
For instance, there are a bunch of small, overtly racist / misogynist / etc instances that have amplified harassment campaigns against prominent Black people on here. If you're on a server with more proactive blocking, you'll never know about it, even though the targets certainly will if they're on a less actively-moderated instance.
For a lot more history, you might start by reading about Dr. Flowers' experience, one of many stories linked in https://privacy.thenexus.today/start-making-the-fediverse-less-toxic/ by @thenexusofprivacy