Their gender is rather pivotal to the story told by the article. It's not presented as remarkable that these two programmers were women -- in fact, that was quite commonplace at the time -- but rather, the article argues that their contributions have been minimized in the intervening years in part because they are women.
As for the grammatical question, there are various theories why "woman" and "women" have started being treated adjectivally, e.g. [1]. I agree that it's problematic, but it seems to be a response to equally problematic baggage attached to the way the word "female" has been used in other contexts. In other words: grammatically, you're absolutely right, but it turns out it's not _really_ just a grammatical question.
As for the grammatical question, there are various theories why "woman" and "women" have started being treated adjectivally, e.g. [1]. I agree that it's problematic, but it seems to be a response to equally problematic baggage attached to the way the word "female" has been used in other contexts. In other words: grammatically, you're absolutely right, but it turns out it's not _really_ just a grammatical question.
[1] https://slate.com/human-interest/2016/02/when-you-should-use...