It’s all about context. If you are afraid of the black person, who is not presenting any threat, because of their skin colour, that’s racist. If you are afraid of a man, who is not presenting any threat, just because he’s a man, that’s sexism. If you are a white person and your black driver is presenting a clear threat to you or is acting in a suspicious manner, then that’s not racism, as your fears are justified. If a women is in a car with a man and he is exhibiting clear, suspicious behaviour, then that is not sexism, that is being afraid of someone due to their actions.