Earlier quoted context omitted.
Forget the connotation 'horrific'. Are you asking why we should work to stop this behavior? Pardon me for assuming but here are my thoughts - Because it's literally systematically oppressive. This behavior makes an entire gender less likely to participate in our field. That's bad for the gender and it's bad for the field. Isn't that enough reason to work to fix it? So what if there are non-malicious explanations for…
I'm saying that it's impossible to fix. If you're a short white guy, people will always initially assume that you're not a pro basketball player. Again, as long as you're not overly zealous about your assumptions and willing to accept when they're wrong, it's not discrimination or "systematic oppression". Feminists try to turn this into a gender war, but it's really not. It's the circumstance of any minority in any h…
Being female is not a natural impediment to programming. So, even if you're correct that gender assumptions are valid (and apparently OK) because of the prevailing gender makeup, it is not impossible to fix - you fix it by changing the prevailing gender makeup. (I don't agree with that assumption, but let's grant it for the sake of exploring the other point.)
If part of the reason for the prevailing gender split is the attitudes that are caused by the prevailing gender split, then sure, you have a chicken-and-egg problem. But it's far from impossible. You can, for example, change one half of the equation by social expectation manipulation. Or change the other half by affirmative action measures. You may think the cost is greater than the benefit, but it's not impossible.