Your post touches on the academics of the subject, but not the real-world nature of it.
The concept of prejudice has all but been eradicated in the real-world. Fact: whites are more likely to be a victim of a black person than a white person. Prejudice would lead me to be more wary of blacks, but that would be labeled racist in today's politically-correct climate. Fact: overall, men are much stronger than women. Prejudice would lead me to ask a man for help instead of a woman, but that would be labeled sexist.
So yeah, keep telling me how something is defined in a book...