Sometimes topics like this start to not make sense because the greater understanding/explanation is missing. The bits that get glossed over/skipped/missed out add up and you end up with a conclusion that leaves you surprised, but also confused.
Honestly this video doesn't really give someone much to work with and doesn't mention dynamic range nor exposure in relation to the camera recording the image. The concept of the colours also is not properly covered at all (eg he says that colour is subjective but at the same time doesn't explain it fully - not even touch upon how things like hardware calibrators for monitors and printers can work if colour is only ever subjective).