Maybe hate is the requirement for love? To truly appreciate pleasure, don't you need to subject yourself to pain?

Hatred in itself can be a good thing. If we didn't hate genocide, would we act to prevent it? Hate means that you recognize something as bad (in your viewpoint) and if given the means you would act against it.

I hate homework, I don't like it, and if I was a teacher, I wouldn't assign it. But does that mean I won't do it? No, that's stupid. If I don't do homework, I won't understand the material or what questions will be asked.
Same with your "hatred". Say you hate "Person A", your boss. If you hate "A", that means you perceive something wrong with him, and you can act on that hatred. You could file a complaint, you could quit, you could do a number of things. But if you committed homicide, that would be stupid. Hatred, if properly channeled, can lead to better things. If incorrectly channeled, leads to your own self-destruction.

Think about it.