On YOUR server you can do whatever you want. You are the admin, so it’s logical that you can perform any action whatsoever on your local copy of everything that has been copied there. (If you couldn’t through the UI, you certainly could through manual changes in the DB.)

Nothing you do because of this will be successfully federated to anywhere other than your server. That would be a major security issue, after all anyone could maliciously set up a server and make random changes affecting everyone.