Alvin, this is a brilliant question. I think you’re the first person in all of this — since the very beginning of the manifesto episode — whom I’ve seen find the heart of the whole issue.
Since you navigated right to the beating heart of this topic on your own I bet you have a better answer than I do but I’ll give you my $0.02 from my years working in supporting women in engineering.
If someone interested in improving the diversity system were to talk to the head of diversity (which is ideally the CEO of the company) and ask how the current structure is implemented you’d hear a ton. I bet the diversity folks have a ton of ideas that need to be implemented but for which there’s currently no support. And I’ll bet they know full well if their candidates are only passively interested in doing the work of software engineering (as the manifesto suggests might be the case) or if they’re aggressively interested but trying to evaluate each company for toxicity (as is my experience).
I’ve hired a number of women into technical roles and many of them have told me later on that a significant factor in their decision to accept the job offer was the fact that folks seemed to listen to them. They go from interview to interview proving they can do the work and silently evaluating companies for how much condescension they have to put up with. Every woman I know in engineering has so many stories of being mistaken for a recruiter or telling somebody “at my last company I built product X on technology Y” and then the (male) explains to them in detail how technology Y works. My companies have offered them a place where they just won’t be personally insulted and that’s been a huge selling point for them.
So if I were to bet my own money I’d bet on this: If we did a lot of research in what is liable to attract women to engineering and keep them there the largest single factor would be ensuring they don’t have to put up with men who feel little hesitation discussing a woman’s fitness for their jobs.