Curious to hear other thoughts about this, as I'm trying to keep !simracing@lemmy.ml active, but might suggest to move it elsewhere if a lot of people prefer not to interact with lemmy.ml communities
You can't really. I mean you can block an instance, but that only hides the communities that are on it - you'll still see the users. The only way I know how to ditch the users, besides blocking each one individually, would be to make a new account on either dubvee.org or Lemmy.cafe where all 3 of the big 3 are completely defederated. Think of those instances as troll-blockers, working hard to keep the Fediverse pleasant to converse in:-).