I do not believe that hate solves hate. I also do not believe that hate is an unforgivable sin. If someone used a racial slur 20 years ago, people will often try to take that person down with it now. Are we that unforgiving? Paul persecuted the Christians; yet when he was converted, the Christians forgave him of his transgressions even though some of them were very serious. To be honest far worse than a racial slur.
If someone used to harbor feelings of hatred, and now they know why they were so wrong, should we not forgive them? Or is hatred an unforgivable sin? I think as a society we need a little more forgiveness in our hearts. It is funny some of the most hateful things I have ever read have been from people decrying hate. Let's be more like Christ be forgiving and less judgmental. Christ once said, "Let him who has not sinned cast the first stone." That was, of course, a paraphrase. I know I have way too much sin to be condemning my brothers and sisters.
If someone is truly being hateful, we need to show them the power of love and not try to out hate them. That benefits no one.