Honestly, my advice to anyone running a fediverse instance is block/suspend other instances liberally, for whatever reason you like.
The fediverse is built on protocols that handle privacy imperfectly, and the popular fediverse implementations are woefully lacking when it comes to tools to deal with harassment and abuse.
You don't have any obligation or moral responsibility to federate with instances you're not comfortable with. You're not a common carrier and the fediverse isn't going to fall apart if you don't federate with everyone.
Personal instance for @gid.