I ended up implementing a way to remove a user but keeping them in the tree, that should probably be the default action when deleting someone.
I had to because I realized that npub1jk9h2jsa8hjmtm9qlcca942473gnyhuynz5rmgve0dlu6hpeazxqc3lqz7 (npub1jk9…lqz7) is flooding wss://pyramid.fiatjaf.com/ with a million notes with ugly images but he has invited a ton of people that I don't want to remove.