See the rest of my sentence. I was explicitly talking about things in themselves, and not how they appear to an observer.

The original comment I responded to

A few people talk about wavelengths of light, but I doubt that they want to assert that the light in question, as it traverses space, is actually colored green.

Anyone talking about light in the optical range as it traverses space is likely to talk about the color of that light, and assert "that's green light". More generally, outside the optical range, they're likely to talk about the type of light in terms of frequency bands.