Confirmation bias is tricky. As pertains to news, it basically says that we tend to seek out the sources that confirm our existing bias. We tend to watch just the conservative news, or just the liberal news depending on whether our own beliefs lean toward conservative or liberal.
Not only that, when we view centrist sources, we tend to think of them as leaning to the left or right rather then the center.
Which means we are not getting the whole picture of news and events in our world.