Not true in the slightest...
Red, Yellow and Blue are the primary colors in color theory.
They're the colors that can't be created by mixing any other
colors on a palette. RYB being taught as primary colors isn't
some attempt by elementary schools at dumbing down fact
so their students can grasp the concepts more easily.
CMY (and Black) are the primary colors used in color printing,
not art. No painter has ever mixed CMY (and Black) on their
palette. Magenta wasn't even created until the late 1800s.
Cyan isn't even a single color; it encompasses blues and
So as far as art theory goes, Red Yellow and Blue are the