Ever heard of Charles Whitman?
When you get trained to kill, after a while it becomes just another job, some people enjoy their jobs a lot, and when you run out of people to kill, well.. This is what you get. Welcome to humanity
I never condoned killing the animals over there, but at least they aren't sitting on top of an observation tower with a hunting rifle. Even thou If the targets are right, that's just what's needed. For the most part, humans are disgusting/vile creatures