I have a friend who is quite liberal. She listens to Rush. He drives her crazy - she disagrees strongly with almost everything he believes (and everything I believe) but she listens.
I believe one reason his opinions don't drive her away is that he is polite even to people who disagree with him. Liberals, OTOH, tend to insult those who disagree with them (and their humor tends to be either crude or mean). They drive away everyone who doesn't agree, and wind up with lower ratings.