I'll roll in here (and yes this is one of those ex-cop posts). I will start out by saying I never had the honor or the responsibility of serving in the armed forces. While what our troops are doing is not police work, there are very real similiarities in the dilemnas faced by both in "shoot/don't shoot" situations.
Like the soldiers in Iraq, you are not blessed with psychic powers when you walk into a dangerous situation where potentially people have both the mental mindset and the means to kill you, and particularly when they are not dressed in a visible "I am the enemy" uniform. In police work, you go through regular training in "shoot/don't shoot" scenarios, which complements a very real dose of on-the-job experience. In the military, it's all on the job, and it's constant, everyday stuff, depending on assignment.
One saying that stuck out in my mind from a use of force instructor was that "It is better to be judged by 12 than buried by 6". By that he meant that if you shoot, you will be judged upon what factors moved you to pull the trigger, which can be ******, but sure beat the scenario where you DIDN'T shoot, and were killed for that decision.
The great line from Patton comes to mind "The object of war is not to die for your country, the object of war is to make the other poor bastard die for HIS country".
What I think some of you are losing sight of is that you do not have the freedom (or shouldn't have the freedom in a chain of command and in a military situation) to engage in an inner moral debate about "what if this is an innocent life". The consequences of hesitation are widespread. Every soldier is responsible for each other's lives, and the hesitancy of one might kill them all. It would be nice if the only person who paid the price of hesitating was the one going through the mental exercise, but that isn't how these situations go down.
I think Mac and the details of how these people were released got it right. We have been pretty harsh sometimes on this board on how the military justice system has worked, but this is one of those times that they probably got it right, no matter how bitterly ironic the outcome is.