Hatred is caused by neurochemical secretions of the brain. While a person is harboring hateful mental conditions, the brain is unable to achieve the proper neurochemical balance to achieve Love, Happiness, or any other positive, lasting emotion.
Hatred is the ultimate enemy of happiness and it must not be given any toe-hold within the mind, exept in the rare case of genuine Evil acts. There is nothing wrong with hating evil things.
This is why nations, races and organized religions use evil=hatred to control their populations.
Teach the people to hate or view homosexuality as evil and birth control immoral, and you have more tithe. Especially if you're willing to wait many generations.
Teach the people to hate another religious group or believe them to be evil, and you can make good people do bad things.
Teach people to hate or view as evil/lesser someone of a different race, and they will take everything and enslave them without remorse.
Teach someone to hate everything American, and they'll murder innocent people in the name of Allah and feel justified.
Teach someone that being filthy rich while there are starving and poor amongst us is not evil, and they will be billionaires while people who are their 6th and 7th cousins perish for lack of a good role model, education, health care, food, and shelter from the elements.