For the same reason they ignored the entirely successful conclusion of Operation Swarmer, after wetting their collective pants over it when it started.
You all DO remember Operation Swarmer, don't you? It was the one that completely disappeared from the MSM radar when it became apparent it would succeed -- contrary to their paranoia and bias.
Operation Swarmer? All I heard about that was the MSM carping that it hadn't resulted in any fighting or any dead terrorists and that it was just "political window-dressing." I actually heard that on a local news broadcast! And of course if it had resulted in massive fighting and lots of deaths, the same news media would be screaming about America's "heavy-handedness" and "alienating Iraqis."