The real question is why even with those techniques so few of the high-paying high-ranked jobs are held by historically-marginalized people, not why the country is using the extremely effective tool of affirmative action to mitigate that grave injustice.

(Citations for the efficacy of affirmative action: https://arstechnica.com/science/2012/02/granting-women-a-com... Bonus! It also improves the collective outcomes.)