Radicalization

Scenario Example

You are out shopping with your family when you see a Black woman arguing with a customer service employee. Overhearing the conversation, you realize that she had been stopped by security because she apparently didn’t pay for one of her items. Frustrated, the woman shows the security officer and the customer service employee that she did in fact pay for the item, though they still give her hassle. As you walk by, your brother turns to you and says, Ugh, angry Black woman, am I right?

Question

How did brother assign a racial character to the woman? Why do we use the word “character” and not trait? How is what he said offensive?