Cognitive bias in sourcing of information. They give the people enough "variety in choice" (CNN, MSNBC, ABC, CBS, FOX, NPR, and most of the alt media types, too) to make it seem as though it's authentic when the message synchronizes across platforms. The outliers are labeled "conspiracy theorists", and they've even got Alex Jones types to help them paint the archetype in people's minds to reinforce the idea that anyone outside the groupthink on specific issues are loonies.
Long/Short:
It's hypnosis and persuasion crafting realities that are divergent from objectivity.