Well, you have to understand that those people being purged, and openly shown on twitter as antifa aren't anyone high in the group.

Every four years, the "generals" retreat, cut communication with the "outside top", and they flush the whole thing.
They are useful idiots, but every four years they build themselves a new crop of useful idiots.

This way they maintain control because the "new kids" are fresh, so they can't start asking for more from their handlers.

And that "top" is now, obviously, CIA/FBI swamp.