It's also pretty clear, based on the experiences of women who have an interest in technology, that they experience hostility, sexism, and nastiness, many enough for them to quit. If it were just a couple, then I'd think it was maybe a fluke, but when every woman I've talked to in tech about it has said they experienced it, and all but 2 of my female college classmates dropped out of the CS program, I'd say it's safe to say there's a sexism problem in the culture of tech that should be addressed.
My experience has been that women in technology who say they "experience hostility, sexism, and nastiness" are experiencing the exact same environment that the men they work with experience. Men who work in the primarily female field of nursing experience cattiness, back-stabbing, and undermining cliquishness. Are women in nursing inherently sexist? No, of course not. Men are just not used to the dynamic of a primarily female workplace, and the same holds true for women.
Try this, if you are a guy in tech who doesn't get it: When you encounter a reasonably good-looking (by your standards) woman with a similar professional background, is your thought process about her professional work (e.g. language or OS choices, server configurations, algorithm ideas), or is your thought process about how you might be able to get her into bed? If it's about her work, congratulations, you aren't part of the problem. If it's about the hope of bedding her, then you need to pay attention and make sure you're thinking with your brain rather than your dick. If you don't know for sure, err on the side of professionalism and focusing on work, and let her make the conversation personal if she wants to. If you can't stick to those rules, you are part of the problem.
So, the woman who finds a male nursing co-worker attractive is the problem with the under-representation of men in the nursing field? Men interact with men differently than they interact with women. Women interact with women differently than with men. "Professionalism" that attempts to pretend that's not true is doomed to failure. There are plenty of fields that are balanced in gender representation. There is absolutely nothing inherent in IT professionals that they create a more "sexist" environment than there is in nursing or teaching professionals. Attempting to blame the behavior of those already in the field is disingenuous, uninformed, and insulting.