It's true - a woman can take pride in being caring, empathic, etc. A man can (secretly) take pride in being aggressive, competitive, etc. Blacks in America are constantly told to take pride in being black, but aren't supposed to take pride in any specific traits - just specific events in history. (I saw an Indian woman, trying to compliment a black man, say very sincerely that blacks were good at sports. He was not pleased. The fact that this could seem funny is strange.)

Absorbing all cultures into a single culture would be bad; I say this based on experience with genetic algorithms. If we eliminated race, it would increase cultural entropy. And I've got to think there must be similar advantages to having different races, as opposed to churning out people with SNPs chosen independently with probability proportional to their worldwide frequency.