2 - Thanks for the clarification, I stand corrected!

One doesn't need millions of users to have a healthy community, and if communities are built around being divisive hate machines, there's no need to welcome them, they can stand alone as their own ignorant islands. You can't force integration between sane society and the intolerant. The hateful intolerant have to be moderated and told to go piss up a tree.

Gab only turned off federation after it was clear they weren't welcome anywhere.

I don't disagree that growth of the fediverse would be a good thing, but not in an unmoderated fashion. The example growth you give is a great example of the wrong way to get growth - nobody's trying to re-create Twitter. The style? Sure. The content? Nope.