I mean it’s all been a decision from Admins. Let instances defederate from each other but let users decide on their own. A warning label would be enough, something like: your comments/post on this instance wouldn’t be seen from other users of your home instance or something like that.
I mean the solution actually is, people have Lemmy accounts for different stuff, this isn’t a practical solution when the Normie’s hit Lemmy in the future.