If the author is wrong, that there definitely isn't some inherit genetic behavioral bias influencing job choice, than the bias is happening before students finish highschool.
I'm a proponent for an "early bias" theory because of far lower female graduation and entry level application rates to CS jobs. If less than 25% of CS graduates are female, which is currently the case, it strongly suggests that attempting to make the engineering team 50% female will result in a lower hiring bar for women. That means that the overall point of the authors manifesto, that programs designed to specifically increase the ratio of female engineers are unfair, is true.
We need to do something about the low number of women going into tech fields in school. Punishing companies for not hiring women when the vast majority of candidates are men is a perverse incentive that is biased against men and doesn't fix the real problem.
It's like punishing someone for taking more yellow onions at the market when there's 3 times as many nice looking ones as white onions. The right way to fix the imbalance is to increase the supply of white onions. In the real world, farmers would begin switching to white onions and the supply would increase. Unfortunately, our supply of women is governed by a mostly government run school system that doesn't exist in a world of supply and demand and likes to shift the blame for their ineptitude.
Fixing this at the education level would mean owning up to a mistake. It's much easier to just fine everyone to make it look like you're fixing a "problem" caused by inadequate regulations.