You make the false assumption that those positions belong to whites to begin with. Wrong. Supposedly, those positions should go to the most qualified person. Since many times non white people are not given opportunities, many times they won't get a position even when they are the most qualified person because they aren't even considered.

The new policies try to compensate for that. For example, blind interviews. Funny how once this methods start being used to assign positions, more non white people started to be hired. Now more rational and objetive methods need to be used for promotions. In the medium-long term that would be good for society.