> What do you think is wrong about Mastodon?

The same problems as always. Allow federation and you get...

- federation wars and moderators conducting these wars using their own users as hostages - I left Mastodon years ago when some particularly dumb morons decided to do bitchfights regarding Israel / Palestine. No I'm not interested in your pointless squabble, but I do care when I suddenly don't see posts from a bunch of users without even getting a notification...

- Mastodon-specific, when you move your account from one instance to another (e.g. as response to above-mentioned BS) your followings and followers migrate - but all your posts and media do not

- spam, trolls and griefers abusing the system, up to and including sending around CSAM material that inevitably gets sucked in by your instance, making you liable in the eyes of the law

- security issues. Mastodon has been full of these, no thanks I don't have the time to be constantly on guard lest I be exploited from above-mentioned griefers.

- other instances not giving a flying fuck about moderation or abuse going out from their instances.