@juergen_hubert One of the many reasons I've considered migrating to #hometown is because of the greater user control over their interactions. Much like other platforms, a good way to limit harassment is to require someone to be your follower before they can interact with or see your posts, and also require confirmation to be a follower.
As an admin of generally small communities, if a user were being harassed they would know that contacting me would result in my helping them set that up, and I would also look at where the traffic that the harasser is using originates from. For more extreme options than simply defederate from a harasser's preferred instance, I could see even setting a firewall rule to block an entire ASN from connecting with my instance if that would limit their access, depending on the style of the harassment.