Hate can be a deeply stimulating emotion. The world becomes easier to understand and much less terrifying if you divide everything and everyone into friends and enemies, we and they, good and evil. The easiest way to unite a group isn't through love, because love is hard, It makes demands. Hate is simple. So the first thing that happens in a conflict is that we choose a side, because that's easier than trying to hold two thoughts in our heads at the same time. The second thing that happens is that we seek out facts that confirm what we want to believe - comforting facts, ones that permit life to go on as normal. The third is that we dehumanize our enemy.