It would not be hard to adapt keys to relays in a transport-agnostic way. Just add a new event kind 3xxxx which means "I am a relay" with tags declaring relay address under different transport (wss, onion, etc).

> The reason that devs keep wanting to put logic directly into the relay is that nostr has no official spec for moderation of a relay and the nostr world is very opposed to talking about moderation or making it easy, so it is a green field.

This misses the point for me. Relays largely already have everything they need to do moderation (nip 56, auth, and deleting stuff), which means the best form of moderation is going to be implicit on the protocol level, explicit on the human level.

But I agree that the needs of a community for policy enforcement neatly match those of any kind of relay.