I frankly think the whole metaphor of affirmative action is misguided; we defend in general politics as the best we can get, but the real issue is building a movement that is organically multi-racial. The barriers to that are real and failures deserve not self-flagellation but concrete responses.
Issues matter- even where many folks of color agree with the general left on broad economic fights, they often feel the need to deal with the life-and-death fights of police brutality, immigration or other do-or-die fights. And inevitably, that leaves many issue fights less diverse. That doesn't mean it's terrible that some groups will be whiter than others, but it does emphasize a broader coordination so that the movement as a whole has diverse leadership.
But it's worth noting a basic reason why many movements are monochromatic, which is basic economic privilege that accompanies racial privilege. Politics takes time, a luxury a lot of people don't have. The more an organization depends on endless meetings, the more its membership will be white. That is a correlation that I have found almost ironbound.
Multiracial groups I have been involved with always have strong leadership who make lots of decisions, because that is the only way you end up with meaningful participation in decisions by people of color, since they end up lost in the crowd of mass meetings.
One of the reasons I became increasingly attached to elected leadership versus "participatory democracy" methods is that the latter almost always seemed to lead to less diverse leadership.
-- Nathan Newman