I've done this before and it's easy.
Simply tell them with every claim they make "Yeah but you're wrong and I'm right"
Then when they demand sauce refuse to do their bidding and tell them if they really want the truth to keep searching for it.
And then (very important) every single time they so much as look at you tell them "you're wrong and I'm right" as often as possible.
They will get overload and shut the fuck up.