Here's a few of the factual errors:

>They’ll launch into a treatise about how the Three Primary Colors

They'll try to teach you Subtractive colour theory. Artists don't actually work in three primaries, however the idea of 3 primaries form the basis of subtractive colour theory. An artists knows you simply don't get brighter colours out of darker ones.

>Primary Colors produces the Secondary Colors (orange, green, and purple):

The colours shown here are additive colour mixes, not subtractive. E.g. Magenta is not Purple. Purple has a single wavelength, magenta does not.

>infamous color wheel you probably learned in school

It's based on Goethe's colour wheel, it's artistic not scientific. (As limited by the few amounts of colours available in earlier times.) Although it's still a decent representation of colour than the result this author produced.

>Doesn't stand up to scrutiny/ Three colors of ink which, when combined, produce all others: cyan, magenta, and yellow. (Black is included as a money-saver — black is the cheapest and most common color; it’s cheaper to have a black cartridge than to dump ink from the other three.)

CMYK does not produce a full gamut of colour, not anywhere near it. Black is not included as a money saver, but because CMY simply doesn't produce a decent 'black' and there can be registration issues. What CMYK does produce is a nice compromise of commonly occurring colours, however you won't get a vivid blue, green or red out of it - there is simply no building blocks in those colours to produce a good version of each. Instead you'll get a purplish blue, a yellowy green and an orangey red. This is why printers have 'spot colours'.

>But wait! I thought the “Primary” colors were red, blue, and yellow, not cyan (bluish-green), magenta (bluish-red), and yellow.

Not only does the diagram falsely misrepresent the results of mixing of CMY colours(e.g. it should be a dark mess in the centre), but it also falsely represents the individual colours themselves. It's actually pretty difficult to get a computer screen to display a true Cyan, which is not, in any stretch of the imagination "bluish-green".

At this stage the author has created a bunch of confusion, seemingly his own because he doesn't truly understand what is going on here. The actual difference between additive and subtractive colour aren't explored or explained. There are lots of common school boy mistakes like assuming subtractive mixing produces similar colours to additive mixing, e.g. he shows that purple is akin to magenta(it's not), or that you can get any colour your want out of mixing three primaries(you can't). Or that RGB, or CMY allows for a full gamut (neither do.)

>This isn’t adding up. Let’s turn to science.
From here the article gets better, but it trips a few times before getting to actual physiology.

For a short while he talks about the 'magenta' problem, which actually is well resolved. It's called an extra-spectral colour, it's not generated via a single wavelength, but rather the absence of wavelengths from white light. Oddly later he mentions this.

>Opposites

"Complements" rather, are well resolved scientifically, there are two sets of complements and two colour wheels to demo these. Since he's talking about eyes, he should just focus on additive colour.

The wheel the author has created is utter rubbish, it skips swaths of wavelengths and is only interested in preserving 'opposites', which are represented by incorrect renditions of those colours anyway.