It seems to me that the real problem here is that both sides are stupid. When you think about it, 50% of the population is going to be of below average intelligence. A very large percentage of people on either side are going to be utterly ignorant about pretty much everything, and simply believe whatever they think sounds good. They listen to smart people talk about things, and then get a distorted version of that in their head, and believe it no matter what. They're not smart enough to realise that they could be wrong.
Compounding that is the fact that genuinely smart people tend to talk less and listen more, and rely on logic and reasoning rather than volume and emotion. Therefore, the dumb people in any group are generally going to drown out the smart people in any group.
This means that if you're opposed to a certain group, you're not going to listen to what they say very much, and when you do, all you're going to hear is the shouts of the ignorant portion. Since you're already inclined that way, you'll quickly come to the conclusion that everyone on the opposite side is stupid. And since smart people don't generally hang out with stupid people very much, all the people you hang out with on your side are going to be relatively smart.
As for the Mainstream Media: there may be a liberal or conservative bias depending on the network, but primarily the media is biased toward neither side -- they're biased toward sensationalism. They only care about ratings and making money, and since half the population is of below average intelligence, they cater to the lowest common denominator. This means they're less concerned about the truth, and more concerned about what kind of sensational facts they can dig up to wow their audience, and never mind the boring stuff. Case in point(s): all this Runaway Bride garbage, and Michael Jackson's trial.
Bah. Stupid people. Always ruining everything.
So sayest the Writer of Silly Things!