But you see, where groups of people become a recognizable other and cement themselves into a position that grants them an advantage, then naturally other groups will try to take that advantage from them. Society exists because it is a structure that reinforces cohesion and cohesion means reducing animosity between groups. So within society there is a desire and the mechanisms to address imblances such as these. Where one group begins to dominate it can be in society's best interest to level the playing field. Diversity is a good thing for systems that whish to stay away from local minima.