Purge requires intent.
They left, either through refusing to obey, or willingly. That could be called an exodus, migration, evacuation, retreat. But not a purge.
Stalin rounding up people and sending them to the Gulag was a purge.
People saying, “I dare you to ban me and up yours, Jim,” is an action of a restrained and good moderator. I’d have banned them much earlier for their behavior. They chose it. In a purge, you don’t choose. You are chosen.
Playing linguistic games won’t change reality. Some chose a flame warrior’s retreat strategy. Some just left. But it was up to them.