[kazinator]

> Why choose anything other than the pseudo-default Mastodon.social?

- Because might not be accepting new users.

- Because some other server has a local timeline that is interesting, perhaps catering to certain interests.

- Geographic: it may be closer to you.

- Language restrictions. You want to toot in certain languages, but some instances are English (or whatever) only.

- Some instances run hacked software with useful features.

> why would all problematic users congregate on the same server?

Because they behave in a way that gets them banned in other servers.