How does one learn to hate?

I suppose that if you tell someone a lie, over and over again, that someone will believe it is true DUH! We have seen this with the war in/on Iraq. No one is born with any prejudice. Too bad children have to grow-up in this case but as I often say that one has to have tasted chocolate in order to say that he does not like it, when adults show a tendency to hatred they must have had a feel for it in their younger years. I often think that parents should pass a test before being able to have children. OK I am pushing a little too far here but how can we stop this? Educate? Does this mean trying to make people not to feel what they are feeling? How can we remove this ugly feeling from people's heart? It will never happen. What I wish is for people to have tolerance towards differences. But again, my wish list is growing by the day and I am an idealist.
Here is an Op-Ed that will make you think and that is getting lots heat.