Well if someone made a magazine that's absolutely unique in history and cannot be duplicated then yeah that might be a concern. But, honestly why not make a rival mag or find a simliar one to migrate to? There's plenty of magazines in the sea. If this guy has 18 that are squarely in your wheelhouse and there are no other options, you could make 18 new ones or boogie on over to the next instance.
I'm not saying we shouldn't be fussy about admins being adults and acting fairly. Just that we're still early in the ballgame here and the whole thing of four-mods-owning-800-subreddit things or whatever really shoudln't happen here for any good reason.