Why is it that almost all of my non-lefty friends listen to NPR, while nearly all my lefty friends listen to Rush Limbaugh, Sean Hannity, or Michael Savage?
1. Lefties like to get pissed off when someone on the right says something outrageous. It reinforces their worldview. And especially with Savage, who says stupid things, they can point out errors and say to themselves, "See, they're nuts."
2. Rights listen to NPR because it's relaxing in the morning and, like the New York Times, it's not all propaganda. Also, they like to get pissed off, and they like to point out errors and say, "See, they're nuts."
I've noticed it in the blogosphere. The Leftists go make fun of the freepers, and the moderate/right go make fun of the Democratic Underground. It's a form of reductio ad absurdum, where you seek out places where the other side's argument has already been reduced to absurdity for you, like a boxing champion carefully selecting his opponents.