I think the confusion arises because because people (the author of the article included) confuse "color" and "spectral color". Spectral colors are what you when you look at light of a single wavelength, e.g. a green 520nm laser pointer. Not all colors are spectral colors, e.g. you'll see purple if you look at a source that produces 600nm and 450nm light, which is a color that can't be produced by any single wavelength.

Coming back to the color of the sun, it (the sun + the atmosphere) emits light over a range of wavelengths, which we usually perceive as white.