Only politicians have to pretend that everyone is 100% equal in every way, because they can't afford to offend anyone. pg, on the other hand, doesn't need to worry about that as much because what matters is whether the startup is successful or not. If there is a pattern indicating that a certain group of people are particularly bad at running a business, why should he take the higher risk associated with investing in them?

Because correlation != causation, and applying "pattern recognition" to race and gender is racist and sexist.