It doesn’t matter how flimsy and transparent the lie is, they just need a veneer so they can pretend to believe it. Pretend to be good people with values and standards. Otherwise, they’d have to admit to themselves that the truth is they just don’t care what horrible things a person does, so long as they are part of their ‘tribe’ or it furthers their personal interest.
Probably partly down to at some level people being inclined to believe it simply because it was “on the news”. A good start would be to force any organizations claiming to report the news (factual accounts of past events) but actually pushing lies, conspiracy theories & far-right opinion pieces as news, they should be forced to rebrand. A change in the law to force Fox to either clean their coverage up & report on actual news.