And even if they do not believe it all, even if they listen just because they like to get worked up a bit, there is a perfidious mechanism at work: if five is the reasonable middle between four and six, but people will shout without pause 'twenty!, twenty!, twenty!', then a lot of people will think the reasonable middle must be four plus twenty, so twelve instead of five. (Sheesh, learn proper terminology, Louis)
So you mean that by vocal really crazy wingnuts spouting lots of nonsense people shift further to the crazy wingnut direction, but hold up the really crazy wingnuts to say that they themselves are perfectly normal compared to the real loonies even though they are actually insane.