Why refer to these women as 'girls'? It'd certainly stick out if anyone said that a bunch of 'boys' had learned to program a computer – it would be implied/assumed that children were doing the programming.
I've always associated the word "girl" more with gender than age, so it's very natural for me to refer to a woman as a "girl" when talking to someone informally. On the other hand, in my mind "boy" has a strong association with with age as well as gender, but "guy" doesn't. So "guys" and "girls" are my generic go-to words when referring to someone's gender without regard to their age. I'm guessing I'm probably not an oddity, since I acquired these associations while growing up with mainstream media like most people.
The words are ambiguous and overlap with a lot of sexist and even racist (calling all Black men "boy") behaviors, so it is unclear sometimes if a particular usage is sexist
Is that something specific to this particular story? When the police chief says "the boys down in ballistics have their hands full with the shootout last night" we don't assume he's talking about children.
Sure, but the title of this is "Girl figures out how to program giant computer".
"The boy down in ballistics got in a shootout" is not something our hypothetical police chief would say.
The title also implies some level of surprise that 'girl' 'figured out' this 'giant computer'.
It might seem like a nitpick, but stuff like this adds up. I used to call women 'girls' occasionally, but I stopped when I realized that I'd rarely use 'boy' if the gender was flipped.