I'm probably using the terminology wrong. If you block hexbear.net you will no longer see any posts or comments from any of their users. Does that not solve the problem for most end users (not mods/admins)?
Maybe I'm wrong there. I swear there was an option to block entire instances.
You realize people can block entire instances they don't want to see on their own, without it being defederated.
Settings -> blocks -> block community.
Edit: That's not the setting I thought it was. But I'm sure you used to be able to block entire instances.
Edit2: confusing it with an option on connect/sync.