"Both Sides Do It" Is Just a Smoke Screen to Cover for the Liars

The difference is that Fox News LIES about FACTS, and that is a VAST difference. 
Fox News’ fans have little to say about this, except to bark that “all news organizations lie” and immediately turn tail when you demand that they prove it. 
To make that intellectually dishonest claim without any evidence is merely a way of letting the actual, documented liars at Fox News off the hook. And that’s their intention.
Fox News displays this open contempt for facts because it is a right-wing authoritarian propaganda machine, and I mean that literally. 
Fox News does not practice journalism. It SUBVERTS journalism. It is the Fourth Estate's Fifth Column. And you can always find Fox News by following the trail of slain messengers who tried to tell somebody the truth. And yes, the Big Lie works.