I do not like defederating instances for moral/ethical reasons. If that is the mission of the instance you join, so be it. I would only defederate as a last ditch effort to stave off technical or legal problems. Burggit plays in a grey area with the legal side, but I still wouldn't defederate until it's demonstrably causing a problem. I would also support defederating from instances where they are abusing federation to inflict harm on other instances/users.