The Tea Party right's conspiracy theories, methinks, can be explained (absent frank psychosis) as can their trivialization of fact. They divert and dominate the discussion. The moral panic, the existential threat, is thereby excluded from the discussion, just as those advancing facts contradicting their narrative thereby identify themselves as pointy-headed, out of touch, elitist liberals, lacking entirely in virtue or legitimacy, who--wait for it--want to impose their sense of reality on everybody else.
They deny evolution in large measure because accepting it results in loss of control of the narrative. 'God said it, I believe it, that settles it.' If they're wrong about any one thing, they can be wrong about anything and everything. Looking outside themselves or their group, according others' take on reality respect at the cost of bringing their own into question, introducing ambiguity, that's a non-starter. Not everyone is strong enough to be uncertain.