People hate when they don't learn how to forgive and instead feeds the anger and hate that they already have in their heart. Whether it be hate for others or even yourself, we would have to admit that we need forgiveness just to close the wounds that are left open.
Actually there are forgiveness people but seems the amount of them are really rarely. People are doing their natural instinct which is hating guys that they don't like. It's normally and can't just blame them.