I don’t think the root cause here is excessive trust in preferred sources. What’s actually at play here, is most peoples weakness at perspective taking. Truly understanding a given issue requires the ability to have your own perspective and to give equal credence to the other plausible perspectives. Many people do not pause to consider alien perspectives, and are disoriented when confronted with them. Therefore, they don’t seek out alien perspectives in order to avoid the sense of disorientation that would result, and that’s why they stick to media that share their perspective, and even punish said media when it offers alternative perspectives.

People have always been this way, but the Internet and social media are really not helping.