Because intersectionality[1] is something that needs to be acknowledged.
Given the target audience, the proper paragraph about the flaws of the model and how it doesn't address intersectional issues probably wouldn't have gone down well. This small comment, however, ensured that at least some mention was made.
[1] Intersectionality is the idea that different combinations of minority issues will have their own, often unique, challenges. In the video games difficulty setting analogy, think of intersectionality being the advanced mode with lots of little sliders for different things, rather than one scale of easy to hard.
Perhaps the author was using it as a demonstration of how easy it is to overlook the direction of your own escalator, being that she certainly has an advantage over some minorities because of her ethnicity.
The article is about the difficultly of breaking in the tech industry as a woman vs a man. I'm not sure how the mention of 'white men' adds to this argument.
If you want something more objective, this US-centric chart seems to be a good example: http://www.bls.gov/cps/cpsaat11.htm