Another former soldier here. From a country which learned that war means your country is in ruins afterwards - and you will probably have lost someone you love. War is more than just sending heroes out to foreign countries to kill the "bad guys".
Of course, I would expect everybody up to NCO level to be against the conventions, as it makes their life more difficult. Working to international conventions requires judgement and thinking. But of course, life would be much easier if you could fire at civilians at will, use land mines, chemical weapons, napalm and many other toys.
I've seen the video. In addition, I read the official report, which is ALSO available online.
Look for
"INVESTIGATION INTO CIVILIAN
CASUALTIES RESULTING FROM AN
ENGAGEMENT ON 12 JULY 2007 IN
THE NEW BAGHDAD DISTRICT OF
BAGHDAD, IRAQ
Report of Investigation UP AR 15-6
MAJ , Investigating Officer
2ND BRIGADE COMBAT TEAM
2ND INFANTRY DIVISION (MND-B)"
The official report shows the following in Exhibit O:
AK found on the ground.
RPG-7 photo redacted, nothing to be seen.
In Exhibit R, we see photos which appear to be taken by the journalist before being shot at. You can recognize in detail a US HMMWV in telephoto range.
So, yes, there was at least an AK rifle and the helicopter crew might have at least good reason to see that a RPG attack was imminent. Exhibit C mentions "Probable Telephoto lens", but is this obvious to trigger-happy kids in a gunship? I doubt it. Plus they don't want to be responsible for the results of not taking action.
(Read paragraph 6 on page 12 of 43.)
The helicopter crew reports and requests permission to fire.
So far, this is more or less an unavoidable chain of events. Most likely a mistake, but given the circumstances, understandable.
But...
Have we learned to shoot at wounded combatants? At people trying to help the wounded? Which are obviously not returning fire?
There's the war crime.