I have a theory that this is the horrible legacy of the Reagan years. Regardless of the other pros and cons of that administration, I think there was a switch from policy to narrative. Cutting taxes increases revenue, welfare queens, the star wars defense shield is practical, government regulation is always bad. Governing on narrative alone ignores actual facts so we have stuff like people going apeshit about a 3% increase in the top tax rate while wealth is rapidly redistributing toward the top. Or people thinking because some guy on the radio says global warming isn't happening that 99.5% of climatologists must have gotten it wrong or want to destroy western civilization for some reason.
ITA. Plus Reagan's scrapping of the Fairness Doctrine, which gave rise to conservative talk radio and Fox News. Also, the tremendous media consolidation which started back then (but that wasn't Reagan's fault, was it?)
But sometimes I think it all goes back to Edward Murrow taking on Senator McCarthy. That's generally considered a triumph of news reporting, but whatever the network that Murrow was on decided they'd never again allow their broadcasters to risk their entire company like that, so it resulted in TV news that was much less likely to take on difficult issues.