*If* the claims that it was merely a wedding party are true, then the US screwed up, and horror and death were visited on innocent people.

The insurgents, on the other hand, are *targeting* innocents. They are targeting truck drivers, aid workers, waiters, Iraqis hoping for a chance to become peace officers...and children. It's not a matter of a split-second mistake that results in tragedy, it's a matter of deliberation that results in murder.

From the linked article (emphasis mine):

"It was a wedding party in which some people were firing in jubilation and the Americans misunderstood and bombarded the place," one official said.

Is the calculated beheading of a non-combatant the result of a misunderstanding?

Amid the conflicting reports, a joint US-Afghan fact finding mission flew by helicopter to Dehrawad early on Tuesday, stopping en route in the capital, Kabul, to pick up ministers assigned by President Hamid Karzai to investigate.

Will the insurgents launch an investigation?

Mullah Omar, who has eluded the Americans during their nine-month military campaign in Afghanistan, was believed to be hiding in mountains in Uruzgan.

"There are forces from Kandahar with the Americans following Mullah Omar," [Raz Mohammad, the brother of Uruzgan governor Yar Mohammad] said. "We believe he is somewhere in this region."

So the forces weren't just tooling around, looking for a wedding to bomb, were they? Worst case, it was a tragic mistake. But the insurgents are actively seeking innocent people to murder.

To be oblivious to the distinction would require thinking that falls short even of the black-and-white level.