Yes, additive colour theory is based on red, green and blue (RGB). These are the colours you see if you look at your TV screen very closely.
Subtractive colour theory uses cyan, magenta and yellow. In printing black, abbreviated ‘K’, is added for contrast—CMYK. These are the inks used to print the dots you see if you look closely at a magazine photo.
I think people are confused by this because they’re taught a bastardised version of subtractive colour theory, using red, blue and yellow, at a very early age.