Because the marines who first said the Iraqis were killed by the IED blast later changed their story to they were killed in a fire fight when they entered their homes. IF the marines are saying they killed them, why blame Jihadis?
I don't think they lied to cover some freak. I think they told it like they saw it. And the jihadis made a play that worked. And now those men are out of action, instead of killing jihadis, while our media destroys morale.