Yeah, that didn’t make a lot of sense when he was talking about colour theory but quoting someone talking about colour keying. Two completely different topics.
As for colour theory, it gets complicated… for one thing the way the eye perceives colour is not intuitive. The colour yellow for example can be made entirely differently with additive colour(RGB) than with subtraction colour(RYB) and as such there are multiple complimentary colour models. The classic RYB colour wheel is used because that’s the one most people working with classical medium like paint are familiar with and because it’s a more natural method as things in nature don’t usually emit light.
