Thanks for sharing this with us. Glad you're ok to tell this story to us. This gives an inside about those racists. We need more of these stories. I want, to learn more about it.
I also think it is how parents treat their children and how they will give those children awareness of colored people. If they don't pay attention to this topic towards their children, then they don't know about it.
It is also how school teacher teach thier students about racism. To be honest, my teachers payed barely attention to this topic. I had one chapter in my history book about slavery. And one explanation about racism. At least, I didn't feel the passion from my teachers to tell more about it.