I think the issue is having a policy which says;
We are going to hire 6 people. But all those people have to be black women.
Thats not necessarily going to help black women in the long run, if every male in the company thinks they aren't up to the standard and only got the job to tick the diversity box. It just leads to resentment and the idea that white males are being discriminated against deliberately even if they were the most perfect person in the whole world for that job.
The point has to be, if you are employing 6 people who are equally skilled, why are you giving the job to the white male rather than the black female if there's nothing to pick between them as candidates.
The reason women tend not to get jobs isn't because they are worse candidates on paper. They don't tend to apply for jobs without having a much better CV. They often don't interview as well because they lack in confidence and don't bullshit as much. These are things that employers should be wiser about when selecting candidates.
My point is that increasing diversity has to be seen to be fair - in its own way - rather than just a box ticking exercise.
What we don't want is the best male candidates out there to be not getting jobs because of their colour and their sex because all the current jobs available are only open to Diversity Candidates. It means there is a lost of talent and a perception of unfairness.