This is a question for the sake of curiousness; the article writer shot a couple of pictures of young black kids. I can't find any mention in the article, but is this just coincidence or is this commonly done becauses the darker skin is hard to shoot correctly?
It's relatively common and mostly a problem of exposure, especially in group photos. In general you want higher exposure for darker skin tones so that the camera resolves more detail, but at the same time you don't want the background overexposed.