And this, I believe, is the strongest possible argument against discriminatory hiring practices.
If I hire someone who's black, or female, or gay/bi, or any other 'protected group', I want them to know that I hired them for their ability, not to fill some quota. And the only way to do that is to hire based purely on ability.
By setting 'diversity hire' quotas, Google's own HR department is telling anyone who qualifies for any of those quotas that they're not good enough.