Yeah, but small correction: Beehaw only defederated from two specific instances of Lemmy, not the entire system. If you were engaging with a Beehaw community from lemmy.one or other instances that Beehaw is still federated with, everyone sees everything on both sides.

Also, if the Beehaw user really wanted to engage with the lemmy.world or other defederated instances, nothing is stopping them form creating an account on that instance (or any other instance federated with the desired community) and commenting or posting from there.