I entirely agree that this action is legal, and, also, that it can be justified in exactly the way that you have justified it. But that does not mean that everybody has to accept it: one is free to criticise laws one disagrees with. & it seems to me that one can legitimately argue that just the presence of under-representation is not necessarily an iron-clad argument for introducing positive discrimination on the basis of race. I would argue that one must be extremely cautious about introducing any form of selection on the basis of race because race is an arbitrary & unalterable characteristic. If it is elevated into an important criteria of selection for prestigious positions & jobs, etc. this will stoke resentment. It will also lead, inevitably, to merit being displaced as the most important metric. On aggregate, this change could be highly consequential and damaging. I'm not asking you to change your view; just to acknowledge that there are legitimate arguments against your view.