Since we evolved with the scope for all emotions, then hatred must serve a purpose. It's PC to say we should never hate.
We're a pack-social species by instinct. In the early Paleolithic Era each extended-family pack of a few dozen had a hunting and gathering territory that they could cover on foot. Another pack that came close were feared and hated competitors for scarce resources. During a bad year when there wasn't enough food to go around, they had no choice but to fight for it. After examining Paleolithic remains with modern instruments, anthropologists tell us that human-on-human violence was the cause of most adult deaths. More humans were killed by other humans than by all other causes combined. It's fairly common in pack-social predators. Like humans, they have their own hunting territory and woe be unto the neighboring pack that strays across the boundary.
