Creating a space in which a set person has control isn't the problem, the problem is the limitation in who can control those spaces

Reddit doesn't make sense as a comparison because there are no limits to how many subreddits can be created, and communities split off from larger subreddits reasonably often when they don't like the rules.

In Urbit's system, you can't do that. If you don't like what the person at the top decides for your plebian self, then you're SOL.