Equally anecdotal, but I am in tech and have a liberal arts degree, and have a coworker who is the same. I also know a few others. In most cases these are people who found the job market rough with a BA (or MA), and fell in love with tech.

Some universities deal with this demand by offering a "Certificate" or something equivalent in tech for students so that they can learn the fundamentals even though they're from a liberal arts (or other background, but have a degree). Even going back like 50 years, my father studied liberal arts but was offered an opportunity to do an advanced degree in computer science, provided he completed core courses (in additions to the ones he'd already done).

I suppose my point is that this may not be as rare as it seems, and is increasingly common as a BA becomes a dime a dozen (although not intrinsically valueless) and the growth in tech jobs continues (for now).