This is where people get confused. Using race to describe a person is not offensive. Making an assumption about a person based on their skin color is offensive. Acknowledging that a lady is Black is not offensive, but classifying her as an angry black woman without getting to know her is offensive. I admire his audacity to pose an important question, at the risk of upsetting me.
"Where are you from?" may sound like a straightforward question, but if you moved around a lot as a child or you are of a mixed race or cultural heritage, this question can become complicated to answer. Mix in the possibility that the race or culture that you identify with rejects or mocks you, you may be left to feel like an orphan child.