American society aspires to be classless. Harvard wants its mini society to be classless, too. If it uses strictly objective, quantitative standards like SAT and GPA in its admissions process (in addition to legacy admissions), then it will have a mini-society that consists almost entirely of rich white and Asian kids. Since this looks like racism, they take the easy way out and use racial quotas to nudge the admission demographics in the right direction. Since this is literal racism, we find ourselves in today's situation: how do you untangle the societal damage done by enslaving a single race for hundreds of years?
The answer is that admission standards need to be changed to focus on the human qualities that schools are seeking in a way that is race-blind and does not give rich families a way to game the system. Doing so will be difficult, and there may be a few years of adjustment before they get it right, but it will get sorted out.