Well, you can look at it as the rags in question being more inclined to receive such claims with uncritical credulity if they say something like “CCP bad,” etc. They don’t need to lie, and in fact strategically shouldn’t (though some of them countenance an alarming amount of direct lying, here I am thinking of the NYT), they can just accept what they are told by the US government, which obviously dings itself by lying but a) with the source being anonymous, how will you pin it on them without the receiving journalist destroying their career by revealing an anonymous source? and b) they’re the US government, it’s already kind of understood that they have a record of lying, but their position of power nonetheless acts as a sort of font of credibility, especially to US citizens.