“This is ridiculous and worse, is the claim that NO LONG and SHORT WAVE LENGTH MAKES A COLOR!”
That was not stated in the article. You get an F in reading comprehension.
There are many different single pigment reds, in paints.
There are many different single pigment blues, in paints.
Red and blue make purple, they can also make violet.
By adding quite a bit of water to a purple watercolor, you can easily make violet; however, you can NOT make violet into say a DIOXAZINE PURPLE. But....you certainly CAN make a violet shade ( by adding lots of water ) to a dioxazine purple!
OTOH...you can NOT make a COBALT VIOLET out of any old purple.