As we all know, as if forever exploiting or attempting to exploit each other were not enough, a group of sane human beings who have just reached the end of a war against a common enemy of theirs will sooner or later start or continue killing and/or fighting against each other.
The most dangerous people in the world are not the tiny minority instigating evil acts, but those who do the acts for them. For example, when the British invaded India, many Indians accepted to work for the British to kill off Indians who resisted their occupation. So in other words, many Indians were hired to kill other Indians on behalf of the enemy for a paycheck. Today, we have mercenaries in Africa, corporate armies from the western world, and unemployed men throughout the Middle East killing their own people - and people of other nations - for a paycheck. To act without a conscience, but for a paycheck, makes anyone a dangerous animal. The devil would be powerless if he couldn't entice people to do his work. So as long as money continues to seduce the hungry, the hopeless, the broken, the greedy, and the needy, there will always be war between brothers.
What is life but an ongoing war?