This article seems to me rather naive. All colors are creations of the mind, responding to physical phenomena yes, but still mental phenomena. This issue was exhaustively examined by philosophers over the years, and this is what they concluded.
“This article seems to me rather naive.”
Actually not. It explains how we perceived the visible spectrum.
“All colors are creations of the mind”
Indeed. It is impossible to prove that “green” or “blue” or “red” look the same in your mind as they do in my mind. The human eye is a light-sensing device that can distinguish different frequencies and create a mental image thereof. Unless we’re color blind (by human standards), we can agree on which color is which (e.g., “green” is the grass color not the blood color), but the mental image that we see is our own.