I believe one solution to this, is to add another option beside federation or defederation.
Since, if my understanding is correct, federated instances don't actually share content until someone subscribes to the community in the bad instance. The bad content is then shown to every other user in the first instance, needing every other user to block the bad content if they don't like it or forcing defederation.
But on the other hand, that means that someone does actually want to view the content since someone did subscribed to it. So my proposed solution is to limit the content of the bad instance to be shown only to the subscribed users and nobody else. Maybe either by the user when subscribing, to select a limited subscription shown only to themselves, or by the moderator.
I believe one solution to this, is to add another option beside federation or defederation.
Since, if my understanding is correct, federated instances don't actually share content until someone subscribes to the community in the bad instance. The bad content is then shown to every other user in the first instance, needing every other user to block the bad content if they don't like it or forcing defederation.
But on the other hand, that means that someone does actually want to view the content since someone did subscribed to it. So my proposed solution is to limit the content of the bad instance to be shown only to the subscribed users and nobody else. Maybe either by the user when subscribing, to select a limited subscription shown only to themselves, or by the moderator.