Mans Inhumanity Toward Man

Today in class I our teacher brought up a lot of painful things such as the loss of a loved one, humanity messed up priorities like Tony Campolo "Three Things" speech, but what stuck in my mind the most was the clip we watched at the end of class "World of Glory". What bothered me the most was at the beginning, when that child was crying. He knew what was about to happen but submitted to his peers anyways as if disobeying wasn't an option, he wore no shackles nor was there any guns pointed at him. Who could take advantage of such innocence? It was clear that that man was tormented about what he has done at the end of the clip but why did he even participate in this slaughtering to begin with? I'm a firm believer that no one does anything in life without some form of payoff so what was he hoping to get out of that act? I also wonder (being appalled by such acts of inhumanity) if I was brought up in the same environment as the main character in this clip, would I have done the same thing? I would like to think not but then again I don't know what led him do this to begin with so how can I say with surety that I would not. Also if any of you have been watching the world news lately, you know that such killings is still going on today, like the terrorists attacks, school shootings, and Syria chemical warfare on their own people. Is there any hope of answering his questions or is this a never-ending battle? I think it's safe to say that when Armageddon comes, most likely humanity will be the one to blame for our own extinction.