As an example of the bloodshed that arises when one group of people regard another as "the vilest of animals" we have this quote from the medieval tyrant, Tamerane:
“About the year 800 A.H. (1398 A.D.), there arose in my heart the desire to lead an expedition against the infidels and to become a Champion of the Faith, for it had reached my ears that the slayer of infidels is a Champion and that, if he is slain, he becomes a martyr. It was for this reason that I formed my resolution, but I was undetermined in my mind whether I should direct my expedition against the infidels of China or against the infidels and polytheists of India. In this matter I sought an omen from the Koran, and the verse to which I opened was this: ‘O Prophet, make war upon infidels and unbelievers, and treat them with severity.’”
He ultimately chose India.