Eh that's a bit of a different mechanism. If you bootstrap a platform from 0 users with the core concept being a lack of moderation, then you're likely to attract those who have been banned, excluded, or otherwise ostracized from existing platforms. This happens because those who support lack of moderation but still have a choice to remain are likely to remain on the existing platforms due to network effects.

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. That is, if your signal-to-noise ratio goes down, but the absolute amount of interaction with your platform increases, it may still be worth it.