Here's my understanding. If a company posts a job and receives 30 applications from women and 70 applications from men, you need to explain the reason for the disparity. Why is there such a difference? I think it's generally accepted that in this case in the software field, the majority of the disparity is due to cultural/social factors. And there are a lot of programs dedicated to outreach, education, raising interest, etc to counteract these societal factors. And I think these are good!
The point I was replying to was whether or not some of the difference in application rates could be explained because women, as a distribution of individuals, have a lower percentage that are interested in a particular type of job than men, perhaps due to biological factors. I don't think there are any conclusive studies that have shown this to be a significant effect, but for the sake of argument, I don't think it's unreasonable to consider. Of course, if it's not backed up by the evidence, then I won't continue looking at it.
I think one of the many issues with the memo was that it significantly overplayed speculative (and incorrect) biological factors, while ignoring the many social and cultural factors that we know to be the cause of most of the lack of diversity.