Unless you want to invoke an explanation that involves some combination of classism and good old-fashioned picking on (relatively) low-status nerds because it's easier and feels more natural. Then there wouldn't be much left to wonder.
(Edit: NOT saying we shouldn't point out sexism in tech, but expressing skepticism at the broader cultural narrative around how software people are uniquely ignorant and sexist relative to other professions. Ask ten women who've worked somewhere besides tech for a few years for some stories of sexism, you'll hear plenty.)