Because that's what we pay them to do. Even if they know they are going to fail, if they have not made a good faith effort to do their jobs then they have no call to criticize the other party.
Your link has switched over to a story about the biased mainstream media coverage, but it doesn't really matter as both sides have professed their unwillingness to work with the other. As we do not have a President capable of going directly to the American people and shaming Congress into doing the right thing or at least compromising to get the issue off the front page, this story will play out in the press. As the left largely owns the press, the blame thus will fall largely on the GOP. May not be fair, but that's life. And if the GOP is not at least trying to do its job, I have little sympathy for them.
tl/dr: The time to cry wolf is after you've seen a wolf, not when you're sure there will be one if you go out into the fields.