People often talking about how USA was the good and Japan was the evil in World War 2, but when you see the history of every country involved, you start to find hard to take sides in any conflict, even though I hate nazis I can't see the Russians or Brittish or French as the good side, those were all imperialistic countries that killed and enslaved millions of people before Hitler, and kept doing so after he was gone. I believe one the biggest reasons for Hitler's rise into power was exactly Great Britain and France foreigner politics.
You are very right, humans are nothing more than a sort of animal, that has to kill themselves from time to time because of their behavior and negative influence to nature. Nature can survive without humans, but not the opposite side.
There is no such thing as "intelligence" or "rationality", but we can get more dull than animals, with war as the final end. War is the result of egocentric behavior. For the developing world it's too many child, two for every woman would be enough. For the western contries it's a wealth, that destroys environment and oneself later on.
In schools we learn to behave like soldiers, and parents believe it's cool. We lead a war against nature, and natural rules will compete. Natural rules are relatively fair and similar to God - merciful on the one side, a revenger on the other side, it depends on our behaviour.