Let's take gender, race, food preference out of the equation. Say a person with qualities A and another person with qualities B both interview at a company. Turns out that at the company (and in the industry in general, type Bs are a minority), and there's a movement to hire more of type Bs. If type A did better in an interview than type B, but the company ended up hiring a type B because of the whole diversity thing…
I think another reason we want to hire B is because if we have only As we are more susceptible to group think. It is good to have people of many different types to prevent that.
Is hiring Bs who are exactly like your As, except in superficial characteristics like appearance, really bringing in diverse points of view?