I assume both of those points to be true. That the external system is negatively biased toward certain groups, and that the point of affirmative action is to counteract that harmful bias. I'll even grant that affirmative action has been somewhat successful in achieving that aim.

It's still disingenuous to argue that there is only benefit and no harm when re-balancing the scale here. Nothing irritates me more than intellectual dishonesty, and I perceive it here.