Racism is less prominent in modern days, as is sexism, but there are still many cultures and people who still harbor grudges against certain other races. Most on this planet probably believe in a stereotype or two of another race, even those who claim to be open minded (they probably know less about themselves than they think they do). So long as we classify aspects of life (whether it be race, gender, sexual orientation, or even things like fashion), there will be those who will discriminate based on those minute details alone.
And force people to change their opinions? How would that work? =/