I'm sure not trying to excuse what the soldier did, but with the rules of engagement they have to abide by, trying to figure out who to shoot and who not to shoot, who will shoot you and who won't, wondering why the heck are they even there and what they are accomplishing by risking their lives, all the normal stress of a soldier, Afgan allied soldiers suicide bombing them in their tents, and then on top of that, dealing with the revenge killings of their brothers in arms over burning some books that were being used to send secret messages. It's not hard to imagine that someone might "snap".
Good line of thinking ... exactly how much ambiguity SHOULD we expect our soldiers to be able to bear up under?
For those that haven't "been there" the absence of a good reason, clear vision, set goals really wears on the conscience. You cannot expect someone to serve morally resolute without providing them a framework. That's the biggest issue I dealt with on the battlefield in my role as Chaplain - it eats at the soul. Then you do that multiple times, and you lose close friends, and the ROE is a joke, and there's no end in sight, and your wife is lonely, and you're missing your children's growing up years, and your life is a perpetual ground hog's day of terror. Your circle of friends gets smaller because its harder to make new connections, and the number of survivors (physical or mental) that started out with you is dwindling. I have troops who have deployed 12 times since 2001 - when is enough enough?
I don't know the details about this SSG, but lets say he snapped, and the Afghan version is true. Do we treat him like the Columbine Shooter? Or have WE the people who voted for our government placed him in harm's way for so long, we've got exactly what a reasonable person should expect? Like a neighbor I once had who kept his Rottweiler chained up outside 24/7 365, except when he went out to beat him. Me, I petted him across the fence, and fed him treats as did my kids, and hed wag his little stump whenever he saw us. I figured one day I was going to hear a scream from my neighbors yard, and I'd run out and that dog would drag over his owner's arm and want to play fetch.