The number of women studying computer science rose dramatically during the tech bubble and dropped off after the crash. I think we're going through a similar cycle.
When programming is lucrative and viewed as high status, it becomes a target for feminists and they push for more female coders. When it's not high status anymore (when the funding environment contracts again), girls will stop enrolling in CS as much and feminists will stop targeting it as a powerful job that needs more women.
It's my opinion that most women probably don't want to be programmers/ICs deep down, but in a bubble environment many women will gravitate towards CS because it's where the action is in the economy, and affirmative action makes it an artificially attractive choice for them.
We're depicting programming and software as the way of the future in business in order to hype startups, so if most women don't really enjoy coding, that's very problematic for feminists. So there is huge resistance to the idea that most women aren't that into coding.
It's like James mentions in his memo, from a logical perspective it's completely arbitrary to want to move women into software because it's mostly men, just like it would be arbitrary to advocate for more female miners or waste managers. The key to understanding the reaction to his memo is to acknowledge that it's born out of a feminist anxiety that if software is run by men, and the future of business is software, the future of business is still going to be dominated by men. So in context, his memo is really challenging the idea that women prefer economic equality.