I would guess most languages with a few million speakers have words for a lot of colors. But I think the argument here is that "baby blue" or "sky blue" is not one of English's "base" colors, but is rather within the classification "blue". The difference is subtle, but it's captured in the test mentioned in the article: if I switch from navy to baby blue, and English speaker might clock both as blue. But for a Russian speaker, these would clock as different colors entirely. I believe a similar thing would happen for blue and green between an English speaker and a Japanese speaker.

The perceptual difference is microscopic, and I certainly wouldn't take it as far as the statement in the headline, but it does seem like the difference is there.