You can try to pull them out, but they’ll hop back in. At least in my family, having been severely abused as a child appears to have been the major risk factor

You can try to pull them out, but they’ll hop back in. At least in my family, having been severely abused as a child appears to have been the major risk factor for growing up into a conspiratorial adult. And no wonder. However, asking questions is genuinely a good way to interact with these types of people when they are making a scene. It’s not to try and change their mind, though. It’s to restore an air of calm and decency that gives them a chance to reconnect socially with others in the room. But you can’t be a pushover, either, and it’s OK to just walk away, ignore it, etc. The one thing you shouldn’t do, IMO, is try to change their mind. Your need to do that will be palpable and will fuel the fire.