Daniel Holmgren discusses this in his really good atproto ethos talk — the P2P networks are cool but incapable of delivering on what users expect from modern social media https://youtu.be/1A-0k58TfPo?si=f_d4uoz_I8kMoKDw
Bluesky's moderation actions are generally implemented as moderation labels which take effect at the AppView level. Sometimes they'll take down someone's PDS or censor from their relays, but I don't believe third-party relays are aware of those relay takedowns at all.