You already know about confirmation bias.
Now consider the backfire effect (from You Are Now Less Dumb, by David McRaney, via Brainpickings):
Once something is added to your collection of beliefs, you protect it from harm. You do this instinctively and unconsciously when confronted with attitude-inconsistent information. Just as confirmation bias shields you when you actively seek information, the backfire effect defends you when the information seeks you, when it blindsides you. Coming or going, you stick to your beliefs instead of questioning them. When someone tries to correct you, tries to dilute your misconceptions, it backfires and strengthens those misconceptions instead. Over time, the backfire effect makes you less skeptical of those things that allow you to continue seeing your beliefs and attitudes as true and proper….
When you start to pull out facts and figures, hyperlinks and quotes, you are actually making the opponent feel even surer of his position than before you started the debate. As he matches your fervor, the same thing happens in your skull. The backfire effect pushes both of you deeper into your original beliefs.
This suggests that the daily news — no matter its substance — is grist for a mill that reinforces whatever you already believe.
Meanwhile, at The New York Times:
Imagine a different mission statement that captures the backfire effect:
Because let’s face it: When is the last time a newspaper changed your mind about anything?