I was watching one of my egg headed shows about the prehistoric animals from our planets past, and there was a profound statement made by a scientist about one group of fossils that was discovered. Probably some of the first advanced animals on the planet. And he noted that none of them had any protection from any predators. He said " this was probably the only time that it seems all living things on the planet coexisted in peace". Or something like that.

Ever since then, it seems to have always been animals that preyed on other animals creating the escalating warfare between prey and predator.

The same can be said for humans. There will always be humans with something that another human wants. And just as one human will use force to take it, the one holding the good will have to protect itself. We have long way to go before we as a species will not fight and kill each other.