I hate this narrative though, because it ignores the degrees of bias that each network has. NPR is way way different than Fox News. CNN isn't biased as much as its run by incompetent boobs. Fox and MSNBC are propaganda made for the soft minded.
There are degrees, but regardless of degree they are all left of center except Fox. It'd balance it out if maybe one or two of the mainstream networks leaned slightly right, but no, they're all left.
Fox sprung up to counter the leftwing mainstream media. Then MSNBC went decidedly left to counter Fox. But CNN was always tilted left being founder by Turner. At the very least it'd be nice to think the 3 major networks were unbiased or at least professional enough to keep their biases to themselves, but they don't. I remember election night in '80 when Barbara Walters was in tears and trying to hide it because Jimmy Carter lost to Reagan. Last 20 years that don't even attempt to hide it anymore. The majority of the exec's, producers and on camera reporters for the mainstream networks either worked for the Carter, Clinton or Obama admins or are married to people who did. Quite a few are married to people inside the current Obama admin.
Never could take Dan Rather serious. Just like everyone knows people like George Stephanopolous is a lefty from Clinton's admin who tries to act like he's unbiased but is totally in the tank for Hillary as well as liberal viewpoints.
I know there are reasons for it. Most of these news reporters and producers come from liberal journalism schools and/or are from big cities with liberal backgrounds. Everyone is going to have personal biases but being professionals they should try to report the news not try to shape the news. Now days it's more about advocacy than it is actual reporting.
And everyone knows Fox is to the right. But the constant whining about it on a national level by people who totally ignore the fact every other network is to the left to some degree if not blatantly like MSNBC to ridiculous.
Even as a conservative I know what Fox is but they are the only one's on TV that counter the lefty media. But even though I'm conservative I wouldn't want all the others to be tilted to the right. I'm in favor of independent unbiased media that wouldn't so easily be turned into a US version of Pravda. But from what I've seen the last 15 years I think most libs would abolish Fox if they could and do just that, have a 100% monopoly on left leaning / blatant liberal media. Then again, many on the left do have socialist/communist tendencies.