Such studies sometimes ask about the outlets; for some reason conservatives feel Fox news isn't the MSM, while CNN and MSNBC are.
Asked about their "non-MSM" outlet, suddenly it is VERY trustworthy.
And these stats hold for liberals as well; they feel their outlet isn't the "MSM", but that Fox is and is untrustworthy.
Since the job of news is now to sell ads and not tell the truth, a lot of "supporters" only hear what their side wants them to hear, and not the facts.
The real problem of course is that each party has different policies; but if we as citizens don't agree on the facts and problems facing us, then there is no way to evaluate the strength of the policies against the problems.