Animals can't be evil. They're amoral. They don't philosophize, they don't feel guilt; they don't comprehend life in the same way that we do. Both cruelty and mercy are human constructs. All animals can do is try to guarantee survival for themselves and their offspring. They've all evolved into a specific niche, and these behaviors you deride are just instincts that have successfully ensured the survival of their ancestors, and so were passed on. If you can't handle the idea that animals in general sometimes kill to survive, get a plant