Don't kid yourself. They know exactly what the reality is. They are lying to distort reality to fool the American public, most of whom are uninformed and uninterested. The accuracy of the charge is not important, it is the seriousness of the charge that is.
I don't buy its a smart thing to do. A smart thing to do would admit the mistakes and grow up.
They don't.
Look what happened with the immigration debate. They were assailed and were stung by the response of the public.
20 years ago they would have gotten away with it, but with more alternative sources out there in the media growing, and the major networks losing ground, they are looking more insipid and pathetic.
Truth in the end will always win out.