younger people are more liberal. they're raising families, working 60 hours a week, going to school, being busy, watching bullshit like american idol and generally don't have a clue about what's going on in the world. They know the latest dance steps but don't have a clue what's going on in the news.
older people are more settled down. They read the paper and watch news, and watch analysis of news cause they like the news so much lol. Their kids are older, they're retiring or retired. They enjoy mental stimulation and politics/talk radio or cable news does that. They would shoot themselves listening to the latest Eminem joint on Pandora, but they enjoy hearing smart people talk politics and news.
Younger people are watching less cable news. People on getbig have a hard time admitting that sometimes.