We're due.

As a species that got to be number 1, we have nothing left to express our dominating nature on except ourselves. You don't just evolve out of that in a couple hundred years—you gotta have a nature that is highly successful at doing what it does best deeply instilled. It seems every now and then we have to let it out. It's like masturbating to weird porn. We're ashamed after, say we'll never do it again, but over time the nature needs exercise.

It's just what we are. It's in our nature to kill each other if there's nothing left to dominate. We need it. The best you can do is reject it and try be a better person every day, and not hate yourself if that species number 1 nature comes out at times. Evolution is incredibly slow.

Edit: Sorry if no one wanted to hear that. And it's obviously a personal opinion.