Conservatives don't trust established news sources because content is at variance with their worldview. It's much easier to believe that all poor people are lazy. It's much easier to believe that all Muslims are terrorists. It's much easier to believe all black people are asking to get beat down by the cops. The cognitive dissonance of discarding 60, 70 years of Repulicanism to agree with objective reality, is too large. Especially if that objective reality is sourced by the liberal news media. Bill O'Reilly has framed the situation as an "us vs. them" contest. How many times has he or Sean Hannity used "the left" disparagingly or in horror? They have painted the media and especially educated people as a monolith of traitors, hedonists, socialists whose beliefs are dangerous to the fabric of America. Fox News does propaganda, when they convince conservatives that the sky is green, rather than throw out 50, 60 years of trusting Republicans to give it to them straight, conservatives double down on a green sky.
Luckily, the digital media is on pace to phase out the news media. The Millenial generation is about to hit their maturity date. Most millenial's nowadays aren't just living to frisbee golf, pound tall boys, and chase skirt. They're starting to wake up to the ugly reality that our world is controlled by an elite bunch of psycopaths who are addicted to money. They control the news media that is in place to protect the status-quo, and the status quo is in place to protect the large moneyed interests, the fossil fuel industry, big pharma, the insurance lobby, the prison industrial complex, and the military industrial complex. CNN is fake news too they just don't have a pro-conservative bias like Fox. CNN will truth tell on Trump's health care plan being garbage but, when's the last time they were de-escalating the Cold War 2.0 or running a segment on climate change?
Since most millenials get their news from Facebook, "fake news" is an issue. But, fake news is not brand new. Millenial's know when they're in the supermarket, and they see the Enquirer headline, "Grey Aliens Abducted George Bush", it's garbage news. They can distinguish the same thing online. But, the Bill O'Reilly's of the world have convinced their viewers that all news from Facebook is fake news. And that mutates into All news online is fake news. Which enshrines the TV news source that always tells the news consumer what they want to hear, in protection. And it protects O'Reilly's ratings in a dying market.
Do you think we live in a post-scandal world now? I can almost guarantee that the Christian right's primary news source is Fox News despite Roger Ailes going down for being a sexual predator. I can also confirm that the Christian right voted for Trump despite Trump condoning sexual assault. (You can't just walk up and grab people's genitals. That's wrong. You shouldn't do that. If Trump was exageratting, so what, he's still a gross scumbag.) None of that matters, the perception of family values win out. Tomi Lahren went down for some scandal too. A bunch of old tweets surfaced of her, exhibiting normal drunk college girl behavior, but behavior that is at variance with her wholesome, girl next door, marketing image.