Not sure how much you're kidding, but... that's true for a subtractive colour system, where you start with a white sheet of paper (i.e. reflects every wavelength) and subtract colours (filter out wavelengths) by painting over the paper with crayons. For an additive colour system, where you start with a black monitor screen, and you add wavelengths, the primaries are RGB.
...and, strictly speaking, the subtractive colors that closest match the typical human eye are cyan, magenta, and yellow -- the "CMY" of CMYK printer inks. Using red, yellow, and blue as subtractive colors gets you a big enough gamut for elementary school color mixing, but it won't give you as big a range of colors as CMY.
I legitimately had a huge argument with my (former) roommate over primary colors.
She was more artsy, I was insistent that the primary colors were RGB, she was insistent that they were RYB. We googled. We were both right in some senses.
Hilariously enough, my fiance now works in printing and actually mixes the colors (t-shirt printing).
I haven't brought it up yet because we once had a fight over whether that thing you put outside your shower is called a bath mat or a bath rug (Both are correct in different circumstances)
Totally off topic (except for the fact that "correctness" of an answer can be a deeper problem than checking against a list) but when you look at how the cones in your eyes are connected to the brain to actually transfer color information it's indeed closer to Red-Green/Yellow-Blue (as described in Lab*). That's why we intuitively include yellow as a "primary color" even though you can just use RGB to describe it.
