So I understand that this author and the Google author are saying there are on average biological differences between gender (i.e. there's a distribution between genders which have statistically significant difference in means) which lead to a difference in preferences and behaviours (on average)... but what does that have to do with being an engineer?!?!?!

By that logic there should be more males than females in a highly technical and stressful field like medicine. Oh wait, we are now graduating more female doctors than male doctors https://www.cma.ca/Assets/assets-library/document/en/advocacy/25-md-awarded-by-sex.pdf

It's exactly that biased thinking that "engineering is highly systemized and stressful and rationale and math is hard and women don't like to do math because you know biology so we should just let nature take its course" that's the problem.