This isn't something that is controversial. There is lots of research into this.
https://medium.com/tech-diversity-files/the-real-reason-wome...
http://news.mit.edu/2016/why-do-women-leave-engineering-0615
http://alltogether.swe.org/2016/04/real-reason-women-leave-s...
Are just a couple, actually published research attempts that I found with a 2 minute google search.
Steeped in a culture of sexism accusations, it's not surprising that you'd hear reports of sexism from women leaving the industry.
A man doing the exact same thing (and many men do leave tech) would say their boss was an asshole, or they hated the hours, or whatever. Women are prodded and trained to interpret exactly the same circumstances as sexism.
Of course this doesn't mean there isn't sexism. But it does mean that you can't just "figure out the reason that they left by asking them".
He has an unfalsifiable belief.
He asks for evidence, someone gives him clear evidence, well the evidence must be fake.
Assignments just don't drop in your lap, you have to go get them. Praise doesn't just materialize, you have to make sure that the right people know what you did--sometimes with a baseball bat. Everybody fights to get "fast-tracked", although I don't really know what that means anymore outside of large companies.
I knew lots of people at IBM, both male and female, who felt shortchanged and I asked them: "So, what did you do to go get on a better project next time?" Generally the answer was nothing. Several of the co-ops complained that they were just doing menial tasks: "Did you ask to do something more important? Did you demonstrate that you could do something more important? Did you complete the menial task well or not?" Generally the answer to all of these were not.
If you don't complete the menial task well, you're not getting something more important--and sometimes a menial task is important. I have often had the conversation with an intern/co-op "Look, the task sucks. But someone has to do it. It's either you or me, and you're lower on the totem pole right now." If you don't do a good job, you're not getting anything better.
And if I'm doing something interesting and important, I'll be DAMNED if I'm letting somebody take it from me.
You have to offend some people if you want to get ahead. And you may have to leave if things don't fall your way. That's corporate life.
And same sex harassment is probably worse. Ever seen someone whip out his junk at a workplace? Happened 3 times in my life.
One of the primary differences is that a man rarely feels physically threatened in a situation. If I'm working at 8PM with a colleague and nobody is in the office, I'm probably not worried about my female colleague physically assaulting me. The reverse, however, is not true.