I don't see affirmative action as fundamentally bad. Applied correctly and not too heavy-handedly, the privileged will still have equal opportunity to enroll or get the job, per amount of effort they put in, etc. And even if it is a bit too strong, their privilege will most likely make up for it in other ways.

In practice though, it's highly susceptible to backfire effects and is usually on the wrong side of "an ounce of prevention is worth a pound of cure". You can't expect someone who grew up malnourished, undereducated and generally mistreated by society to suddenly bounce back and become a "model citizen" when they get a good job or scholarship, statistically speaking.