Only in Iran?

I think this bears repeating over and over. The media continues to regurgitate the claim that certain IEDs could only have been made in Iran. Yet, there were stories last year that describe how U.S. troops stumbled across a factory in Iraq that made these same IEDs. No attempt at reconciling the "Iran-only" story with this fact is ever given in subsequent stories. Atrios's post cites a Boston Globe story, and from here you can find stories in the NYT, the Wall Street Journal, and the LA Times that all allude to this idea (subscription required in all cases, unfortunately).

Though I'm tempted to make a stronger claim, I guess all I can legitimately say is that no evidence has been provided that demonstrates that the IEDs were made in Iran. But, of course, all we could say before the war was that there was no evidence provided that Iraq had WMDs. Shouldn't our media, especially after that debacle, require that the administration actually provides some evidence for its claims?

My own hunch is that most of the stories coming from the U.S. military are carefully controlled, but in the excitement of trumpeting the 'success' of the occupation, they accidentally let a story through that contradicted their claims that the IEDs could not possibly be made by Iraqis.