actually US civil war mark the begining of modern warfare and the statehood is quite mature in that time, think we gaij about 4 states after the civil war and 2 of them are alaska and hawaii...
Being a soldier in war, it hard to not let go with your humanity, the ability and willingness for a soldier to kill depends on one conviction, its that conviction or self control that allow you to bypass all emotion so you can kill, but at the same time its the same conviction to prevent you from going insane, depend on have you face the problem of killing a fellow men before, you may or maybot understand what i talked about.
It just like you hand a loaded gun to different people, sombody will put it away in a safe, some people will use it and rob a liquor store, military are the same as any society.
About the freehand thing, yours is jot the first time sime one ask me why commander will let these kind of crime happens...Short answer is we cannot lay hand on our own troop if we(the commander) did not see it, in military command, trust is very important, especially so when you are breaking up ur unit and let them fight their own individual battle, upside is doing that will multiply ur unit effeciency, downside is in order to do so, you have to gave them some lattutide, some room to operate. If you have to question the method everytime these individual commander doing, your unit will get nowhere. So as a general rules is , the overall commander do not take side and hand off the sub unit, and you only go after them when you yourselves see it, becuase if you have to take someone word for it, you may ended up taking the whole platoon or company word for it, then you are letting your men command you, not the other way around...