The "Fox News" channel does a great disservice to its audience. That disservice is not that it lies to them or misleads them, or that it pretends to be "Fair and Balanced" when everyone knows it's actually the Republican Party's propaganda outlet. That's why people who watch it, watch it; that's why people who don't watch it, don't watch it. Even though the former won't admit it. It's not even so much that Fox purposefully leads its audience to believe unreasonable things.
Now, I have always maintained that there is absolutely nothing wrong with a political party having its own propaganda outlet on cable TV. Nothing whatsoever; there's no reason why a political party shouldn't have a cable channel devoted to disseminating its propaganda. Whether it's OK for such a channel to call itself a "news" channel, or otherwise pretend to be something it's not, is a separate question, that I won't get into here.
The "news" that we see on Fox, as everyone knows, originates from within a paracosm in which Republicans are self-evidently right about everything, in which inter alia Hitler, Stalin, Pol Pot and Mussolini were all liberals and Washington, Lincoln, Martin Luther King and Jesus were all conservatives, in which everything that happens in the world every minute of every day, and everything that has ever happened throughout history, validates Republican and/or "conservative" ideology, and validates the viewer's desire to vote Republican. The recent easily-debunked Sean Hannity Obamacare pageant is just the latest, and among the most egregious and obvious, of uncountable examples of Fox's execution of its mission to validate whatever it is GOP voters and fans want and need to believe at any given moment.
That's really the disservice Fox does to its audience. Not that they lie or make things up to validate GOP voters' various prejudices. It's that they lead their audience to believe that absolutely everything that happens, absolutely everything that has ever happened, and absolutely everything that could ever possibly happen, validates their desire to vote Republican. The problem is that no such universe exists, no matter what one's voting preference or ideology is. Sometimes the world validates your beliefs, sometimes it doesn't. Sometimes the world demonstrates that you voted the right way, sometimes it doesn't. Sometimes the world validates one ideology, sometimes it validates another. Sometimes the people you vote for turn out to be right, sometimes they turn out to be wrong. Sometimes the policies your side advocates end up working well and as planned, sometimes they don't, and sometimes you get a little bit of both. Some of history's bad actors were aligned more closely to your ideology than to another, and vice-versa.
No; the greatest disservice that Fox does to its viewers is not that it lies to them, misleads them, or pretends to be something it's not. It's that it makes them believe they live in a universe that not only doesn't exist, but cannot exist. To believe it's even possible for such a world to exist, for one party or one ideology to be self-evidently right about absolutely everything, everywhere, always, now and throughout history, is simply unreasonable.
Do "liberal" outlets like MSNBC do the same thing? Are we here at Daily Kos also being led to believe that "liberals" and Democrats are, have always been, and will always be self-evidently right about everything? I really don't know. All I do know is that I don't actually believe that. I tend, today, to vote for Democrats instead of Republicans for any number of reasons, and I could go on and on about what those reasons are, but I don't believe that Democrats are perfect or that the "left" is right about everything and has always gotten everything right. If Daily Kos and HuffPo and MSNBC are trying to condition me to believe that, it's not working.