I feel extremely stupid for noticing this just now.
I run a furry instance which has sfw content but also nsfw, and I'm worried about having the whole instance blocked due to other instances being iffy about furry stuff.
When you visit a remote community from your instance, and if you're an admin, you can click on "remove". Not only will the community stay removed even if users search for it again, but it's also reversible in case you change your mind. (Don't use purge because it'll forget you wanted the community removed and it'll be searchable again).
I wish there was an option to silence a community so that users who really wanted to see something can still search and subscribe, but without it appearing in public lists or timelines, but this is the next best thing.
The huge benefit here is that you don't block the instance's users to participate in your communities nor do you prevent your users to participate in communities that you see appropriate for your instance. Overall it preserves federation which is the main point and strength of federated platforms.
So if you come across furry stuff you don't like for your instance, just remove the community. Thank you <3