Well some animals do act this bad, for instance a chimpanzee will kill for fun, and often when they attack another chimp or a human they will rip its testicles off so that its enemy will not be able to reproduce. just an example of an animal that is as fucked up as humans. Not wanting to start a war here either.
Aren't Chimps our closest relative genetically? Weird. Perhaps we are just violent hairless apes?