"Hate" is not something that we can say is evil. Do we not hate shaytaan? Do we not curse him as often as we can? So why should we not hate those that are his allies? Hate is a natural emotion that everyone has, even the anbiya عليهم السلام. Even more so, Allah has said that He hates certain a'maal and certain people. "Hating" for the sake of Allah is a commendable thing, just how "loving" for the sake of Allah is a commendable thing. We hate those who are enemies of those who are beloved to Allah - this is the basis of the Shi'a-Sunni divide at an emotional level.