I really like this article by Dan Froomkin, although I am not sure if he is exactly right. I don't think that the press is afraid to call BS any longer. The press calls BS on a lot of things, the problem is that they don't call it on the things that matter. If you are powerless then the press has no problem tearing you apart. However, if you wield any power at all, then the press will let you get away with, literally, murder.
It seems that in this media environment the only ones who are willing to call BS on those in charge are The Daily Show, The Colbert Report or Keith Olbermann. Unfortunately, anything they say is done with the understanding that they are being snarky.