I think what this shows is exactly ho biased the media is. Fox has had a conservative ownership for decades and now more liberal people are taking over so they will present the news and issues of the day with a slightly more liberal bias.
Now imagine all of the other networks and understand that their ownership is very liberal.

They don't necessarily believe that they are presenting a liberal view, they believe that they are fair and unbiased. But the truth is that their bias is there.