Well, that's something I hope happens sooner rather than later and that is easier to implement than most nostr stuff...
I'm 100% for creating tools for community segregation. What does this mean? You have a set list of relays and you share this space with anyone that has an overlap in relay lists.
To start, if you think of every relay as your community, and the relay operators as your sanitation dept you communicate with them to keep your community clean tell them to clear out known bad actors and mute the ones they don't take off. From there, everyone will find communities aligned with their values and stay away from the others. Maybe a community doesn't have to revolve around a relay, even better!
The whole point being, nostr:npub1wmr34t36fy03m8hvgl96zl3znndyzyaqhwmwdtshwmtkg03fetaqhjg240 can moderate the community in the way they want to cultivate, and you can belong to the relays/communities you care about and not need to worry about encountering each other or dealing with moderation practices you don't care about.