I guess I'd ask where that source got their info.
Cyan, magenta, and turquoise are the colors used by printers and newspapers
because the colors blend truer in intensity than red, blue and yellow.
As far as I know red, blue and yellow are still the Primary colors.
I call them the Printer's Primaries, and let my students do two color wheels
and compare the differences.
They all prefer the orange made with magenta and cyan,
the purple made with magenta and turquoise,
and even the green made with cyan and turquoise.
BUT, they benefit from knowing the colors available from each because now
beginning to understand how to reach different values and intensities.
Just my opinion-Patti