Are these legit? We don't host the community that they are referring to, so I don't understand what good it does to request it.
Instance 1 is federated with instance 2. Someone posts on a community on instance 1. Post gets federated/copied to instance 2. Instance 1 then goes down forever. Instance 2 still has the post forever. People who don't want the post to be on the internet forever request from instance 2 (and all other instances 1 federated with before it went down) to delete the copies of the post or community that originally lived on instance 1 but was copied to instance 2.