How do I train my dog to not be "racist"?

Okay. What I think is happening is that your dog is very protective over you and your family because it's her teroitry and she knows that the people living right next door to her are are from a different teroitry. I think you need to introduce your pup into your neighbors yard on a leash and around the black kids, make sure this is a slow process. My point is make sure your pup is comfortable and is fully introduced to these people. Once she's in there yard and knows the smell she wil click and understand that there's nothing to worry about.