I think, as the article alludes to, men and women are less likely to consider certain careers/colleges/whatever. So if you ignored gender at a liberal arts school and blindly selected candidates, and the ratio was as skewed towards women as the tech industry is towards men, do you think men would be as comfortable there? Having a gender balance (as well as a balance on other axes that include more minorities) is good for everyone. Maybe that overall environment is better than an environment full of mega left-wing lady commies, or, in the case of tech, "hotshot" male engineers with poor social graces. These are all generalizations, obviously, but I think it's true to the overarching trend.