@atomicpoet so the relays you use are up to you, so definitely you can block relays.
There is a spec to report content and users to relays. The responding to those reports definitely needs both social and technological work.
Proactive moderation tools exist in some nostr apps and also do need work. Using the model of choosing relays you read / write to gives us the ability to have the delegated moderation that we have in the fediverse and lacked in scuttlebutt.