Can you think of any reason why the past or present sufferings of blacks would justify letting a white student get admitted to an elite public high school in San Francisco over a Chinese American student with higher qualifications?
Most people would think that such a policy makes no sense. But it makes a lot of sense -- if you buy the argument that groups have to be represented according to their percentage in the population.
What that argument implies, whether or not people realize it, is that groups with above-average qualifications and performances must be denied the places that they qualify for. Chinese Americans are one of those groups with above-average qualifications and performances, so some of them are forced to step aside in favor of white students with lower academic qualifications, in the name of racial balance.
The "representation" argument started out as a way to allow blacks to get more school and college admissions, jobs, government contracts, etc., than they would have gotten on the basis of qualifications and performances. But once you open the floodgates, you no longer control where the water goes. The San Francisco situation is just one of the many absurdities that follow logically from a desire to have institutions reflect demographics, rather than make their top priority the purposes that these institutions were created to serve.
None of this is peculiar to San Francisco or even to the United States. In countries around the world, the more fortunate are benefiting in the name of the less fortunate.
Malaysia's own prime minister has said that the benefits of that country's preferences and quotas have gone primarily to the more affluent. In India, preferences and quotas instituted to help primarily untouchables now benefit far more people who are not untouchables. Programs to help the more backward regions of Sri Lanka benefited the more fortunate people living in those regions.
In the United States, it is far easier to show where affirmative action has helped black millionaires than to show where it has done anything for blacks in poverty. The fact that helping those who were already more fortunate was not the goal or the intent means as little here as it does in other countries.
Another common pattern in countries around the world is that policies of group preferences and quotas generate hostility from those who are sacrificed. In India, such programs have generated lethal riots and in Sri Lanka they have generated civil war.