The media is increasingly portrayed as untrustworthy and calling an outlet part of the mainstream media is increasingly an insult. The media is no longer trusted to bring people even-handed reporting. People are driven away from the mainstream media and search for their news elsewhere, leading them to instead trust small outlets who may simply be peddling conspiracies. This inherent distrust of the media creates a closed circle of reasoning. Evidence directly disproving a conspiracy theory can be disregarded simply by accusing it of being a coverup orchestrated by the media.
[P1] The mainstream media is increasingly distrusted. [P2] People seek out information elsewhere, leading them to believe in conspiracy theories.