Here's the problem. Bernie Sanders supporters are convinced that MSNBC is biased against Sanders. They certainly are more critical of Sanders and Warren on policy than candidates closer to the center.
My point is that if you're really far left, sources that are only moderately left appear biased to you. So if you're a conservative, a straight-down-the-road centrist giving you the news is going to appear biased. The further right you are, the more biased they appear. So much of how much bias you perceive is based on where you're anchored.
Have POTUS beat into your head that CNN and the like are the "enemy of the people" and eventually you'll start to believe.
Trying to say CNN is balanced is laughable. They are all never trump'ers over there. Maybe not as obvious as msnbc but as close as you can get.