They aren't writing the article for technologists and color-gamut-philes. If anything, they're writing it for people who fly long-haul and consequently suffer from jet lag when they have actual business to conduct.

Talking about the number of colors the LEDs can produce is far more likely to convey to that audience how this is supposed to work than delving into the kind of details you'd probably have to read the spec sheet on the individual diodes to find.