I'm a bit with nostr:npub1q6ya7kz84rfnw6yjmg5kyttuplwpauv43a9ug3cajztx4g0v48eqhtt3sh on this one, the tools already exist, you can block/mute, you can filter words in your client, you can join/create curated/moderated relays. Some people can't/won't do that and leave Nostr, fine, probably its not for them anyway. If we try to impose rules that will affect everyone somehow, it will be worse, it will never be enough, and everything will be segregated instead of open. If someone has a nostr client that is a business, then create a moderated relay, filter on your client and share block lists in your app. That's it.