So he felt more compassion for the Afghan victims of US terror. Great, that makes him human. Maybe he's a conscientious objector, maybe he's an idiot. I don't really care. The fact that he was able to view victims of US terror with compassion sets him apart from his accomplices in Afghanistan.
If he felt compassion for the victims of US terror, then there were a large number of legal options for him to quit his job. Instead, he is suspected of going AWOL, and thereby causing the death of multiple soldiers.