His argument was that given A and B they were choosing B because is a woman, regardless of the skills for the position. Some people here also say the gender diversity programs in google are only for sourcing people, that the hiring process is the same (in which case the author of the doc is wrong in his assumptions).

Also another argument from him was that 50/50 is impossible to achieve and if you do you are being unfair and lowering the bar for one of the classes.

The real ratio in unknown, but some people here commented that you can get some approximation taking into account the graduates, the statistics about the applications etc. But for sure the ratio is not going to be 50/50 and positive discrimination is still discrimination.

So, as you said, if you don't know the real ratio why do you have positive discrimination policies? You might be doing it wrong. I think this is the discussion he wanted to bring, review the diversity programs because they can harm the company creating an artificial proportion far from the reality. Given that some other actions could be made like adding more "female skills" to the positions for example. Instead of starting a discussion of this issues based on his biological theory most people pointed at him as a sexits and other stuff. And Google shut him up firing him. So now noone will raise any concern because you can be fired.

To sum up: the big issue is that they are not having the conversation we are having here now, regardless of who is right or wrong.