ah, I understand what you mean. I think for the sake of socialisation many times its best to let subject drop for the sake of getting along with people unless it truly matters. I'm not saying you don't but Ive met quite a few people who don't understand this un-written rule.
yes, people like that there is no point arguing points to because they do not seek the truth, they only seek to humiliate you, even if that means to ignore fact. Worse yet if there are people who follow that person because he is fun even if you prove them wrong with fact everyone will still go against you and laugh at you.
Falling down to there level, or walking away with dignity is the only solution. I find it easy to do so, just keep a clear image in your head that one day they will get 'whats coming to the,' by someone not as forgiving.