> Whereas if you start with the popular platform and progressively remove moderation, you end up with different effects, because you still have the core, non-bad-actor population.

Pretty sure that will just let bad actors back in and drive the good faith users away. You could be underestimating the number of normal users a single bad actor can drive away.

Even when you remove the more centralized moderation, there still have to be some mechanism there to remove the bad actors.