No, Google does not try to mirror content. It tries to provide the best results for users. Results the user wants to click on and are relevant. Searching for "professor style", nobody wants it to return a minority professor style. Even she doesn't, at scale. If she and others did, they'd be Googling "professor style", not clicking, then Googling "professor style for black women" and results would improve/personalize.

Ditto for "black girls": either your looking for porn or for stock photos. What other intentions do you have with such a query? (Besides making a point?)

Google changing results for Holocaust "denial" is likewise wrong. Someone searching for such things probably wants to find all such sites and not just a PC version of history repeating what they've already heard. Otherwise they wouldn't need to be searching in the first place. Same for someone searching "Is the moon real" or "is the earth flat".

In a great market, Google might start "cleaning" up their results to the point of annoying people, who would then switch. Unfortunately no one comes close to Google search, let alone overall lock-in. So we're stuck with whatever Google decides reflects their brand, including fixing up well-publicized queries for people that want to be offended and complain about stuff.

Edit: I search for "best basketball player" and all I see are black guys -- way over-represented. Why doesn't Google bump up Larry Bird to 4th place so there's some more diversity and fight the stereotype? Even worse, Yao Ming is nowhere to be found, what's that say?