But take any of the recent genocides (Rwanda) or even ISIS - innocent people are unquestionably being killed. A soldier hears about this in the news, prepares every day to stop large forces like that, and instead is being asked to stand down. The media obviously plays a large role in shaping the perspective of horrors being done in the world, and I wouldn't argue war is the solution to all but a few problems. However, it is fairly straightforward and morally defensible that innocent people would be alive if other people were killed, and soldiers are prepared and ready to kill.