So in your analysis, there's no such thing as a racial slur?
What you personally think of the term 'negro' is of little consequence. The fact is, the vast majority of blacks in this country reject the term, and consider it a racial slur.
Now, I grant you, the Left has sought to demonize any recognition of human differences--that is, with some exceptions. They cannot very well get away with trying to demonize medical practitioners for recognizing that heredity influences susceptibility & resistance levels to various maladies, for obvious reasons.