Defederation because of harassment seems excessive, surely one can just mute a user? Not sure if I'd be comfortable with your defedation policy. It's one thing to defederate from definitely-illegal-content like CSAM, it's another thing to defederate because feelings were hurt.
Yeah, but if you were to advertise your instance, this is probably something I'd put as a selling point, rather than have some racist person sign up to your instance only to get banned a couple days later.