In most cases, yes. But again, if there is a healthy white or asian man who is not prone to the same diseases and conditions that black women are prone to, and thus would have healthier offspring with a white or asian women than with the black women, why would you want to put your offspring at risk by mating with a black person that is more prone to diseases or disorders?
The same can apply in reverse. White people are more prone to skin cancer, so why would a black person want to mate with a white person and have offspring that are more likely to develop skin cancer?
Because their strengths will ultimately overcome their weaknesses.