I thought that RedK and Rockoon were being a bit shrill calling you an SJW until I read,
"...I would happily accept STEM being 90% male if there was evidence that all involved made a free choice, but there is actually a lot of evidence to the contrary."
In the spirit of fairness, I'm going to first present an article that aggregates support for your general argument in a well organized advocacy piece:
Academic settings tend to encourage examinations into topics that have the potential to over turn accepted ideas. This is actually a significant bias especially regarding fuel for the social justice agenda. So it won't be surprising that there are studies looking into this "problem" and coming out with support for the idea that it's a problem.
Here's another way to view it that is sufficiently obvious that it doesn't need a study.
American society has been actively encouraging girls and women to take an interest in STEM for about 40 years and got focused about it 10 years ago.
The Association for Women in Science was founded in 1971
WEPAN was founded in 1990
The AAUW started the Tech-Savvy program in 2006
The National Math and Science Initiative was founded in 2007
National Girls Collaborative Project
And there's Scientista and Million Women Mentors and... and... and....
My point is that there is AMPLE support for girls and women to enter STEM education and STEM careers. That support has been around long enough to successfully work its influence. And the result has been zero or negative change in the number of women entering college in STEM.
It seems remarkably biased and disingenuous to HUNT for reasons for this in STEM culture. Will you find some male bias there? Sure! Is that male bias the signal you should come away from after beating a drum to increase women in STEM for decades and getting no significant increase in APPLICATIONS for STEM in higher education among women (a class of people over represented in college populations already)?!
Here's what this tells me - A certain percentage of girls and women are into STEM. A certain greater percentage of boys and men are into STEM. The cause of the disparity between these percentages is not due to a lack of support or an exclusionary STEM culture.
This doesn't mean that STEM culture is without male bias. It doesn't mean that it's legitimate to ignore concerns about that bias. It doesn't mean that there aren't gender biases in the greater culture at work on girls and women that keep them from taking an interest.
But it also doesn't mean that men in STEM are part of a pervasive culture of denial when they observe that there are less women interested in their field. It doesn't mean that when all the digital assistants end up defaulting to female that it's part of some blind male presumption. We've been imagining robot voices sounding like Sigourney Weaver for 30 f**king years. In Hollywood, with the exception of Kit, J.A.R.V.I.S, and Max Headroom, EVERY GODDAMN COMPUTER VOICE sounds like Sigourney Weaver. Every countdown sounds like her. Every warning system... every magic talking box.
That voice is a MARKETING decision- not a tech decision. The order in which bugs are fixed is largely a business decision - not a tech decision. And, if you've done enough work in tech, you know that the shortfall in women programmers is made up for in a larger percentage of women in marketing and management.
So, when the various commenters went on their tirade about the SJW nonsense posing as an article in the OP, they had a pretty good point. They weren't demonstrating that they were part of the problem. They were observing yet another irritating, stupid bug in the system of social justice advocacy that allows idiots to cut the legs out from a movement that has legitimate things to do (like saving girls around the world from sex slavery) in order to shit out another diamond-hard nugget of uptight clickbait.