It's not just "war" in the abstract. The context of the video is that there is literally a firefight going on nearby in which U.S. soldiers are under attack. The helicopters shot at what appeared to be a group of armed men ("appeared" because some of the men actually were armed) and then shot at a van that appeared to be trying to pick up "bodies and weapons" (according to the soldier who radioed in for permission to engage the van). In the context of a firefight, that means the van is a potential threat--those wounded and the weapons could go back to fighting U.S soldiers.

This is not a "shoot anything that moves situation." It's a "if you're called in to the middle of a firefight you resolve doubts in favor of whatever protects other U.S. soldiers."

""" Gabriel Schoenfeld, Senior Fellow at the Hudson Institute said of the airstrike:.

It is precisely the presence of weapons, including RPGs, that goes a long distance toward explaining why cameramen for Reuters—pointing television cameras around corners in a battle zone—were readily mistaken by our gunships for insurgents. The video makes plain that in this incident, as in almost all military encounters in both Iraq and Afghanistan, our soldiers are up against forces that do not wear uniforms—a violation of international law precisely because it places innocent civilians in jeopardy. """

Don't get me wrong, I don't think it's never appropriate to second-guess a soldier's conduct in war. But "war crimes" are purposefully malicious actions in the absence of a threat. Not bad judgment calls in response to what you can make out from hundreds of meters away in the middle of a firefight.

This is a war crime: http://en.wikipedia.org/wiki/My_Lai_Massacre.