Why do people have problems with interracial dating?

I mean what's the big deal. What if two people are happy and understand one another. What's the big deal? People are people. Humans have the same emotions, the same physical features, breathe the same air and.....WTF. What should stop two people of different races from dating. The only thing that's different is skin color. I even know people who say that they aren't racist but when they see interracial dating all of sudden they it's a problem. Hating interracial dating is a form of racism.