The gender gap in tech starts with children, is seen in STEM enrollment rates and continues in the job market where a multitude of diversity initiatives exist to promote underrepresented groups in tech.
So, an alternative speculation for the abnormally high promotion rate for women is there are fewer women interested in IT in the first place and companies are scrambling to compete for women because it makes them look better (via diversity initiatives).
There is a great documentary examining actual science on the subject and interviewing both scientific researchers and social scientists on opposite sides of the issue:
https://www.youtube.com/watch?v=p5LRdW8xw70
Should we attempt to combat the gender gap in the nursing industry with the same vigor that we are focused on tech? How about the gender gap we see with garbage workers or psychology?
edit: clarity.