I could care less who calls me racist. There is nothing wrong with learning from your mistakes.
Several years ago I got a new phone, it might have been an iPhone. In any case I was at the building department to fill out some forms and a black lady with her young son sat next to me on the bench. The child was fascinated with the video game I was playing so when they called my name, I handed my phone to the kid so he could play the game while I tended to the clerk at the counter. I figured it's the first chance he ever had at messing with a smart phone. After I got done the clerk called her name, she and her son stood up. She gave me a dirty look and told the child "Give dat man his phone back" as I passed them going back to my seat.
No more. Screw them. You can't be nice to them because they are not nice to begin with. If it was a white mother, I'm sure she would have thanked me profusely and smiled, perhaps introduce herself.
White people don't belong with black people plain and simple.