” . . . Beyond that ignore the trolling or seek to control access via something akin to a caucus. . .”
With great respect I’d like to say that, perhaps, the trolls should ignore Q threads and save us the bother and the space.
With all due respect you’re not going to experience an open thread free of criticism, disagreement and disparagement, ever. Get over it.
That is never going to happen. IMO, best approach is to be smart in choosing whether and how to interact with opponents.