The elves were once immortal, and ruled over most of the continent, from my understanding of. Humans came, we spread and multiplied and conquered. The elves had the audacity to hold power, and to be different. And when that power was lost, there was an all too obvious way to mark an enemy. That is the true root of it, I think. Humanity wishes to see elves shackled. Perhaps we are afraid, or perhaps... simply hateful.