Every time the 'it's all about the light' thing gets questioned someone comes out with the 'if there was no light there'd be no photograph' smart-arse b*****ks.
'It's all about the light' refers to the quality and direction of light, and it's wrong because it implies that the light is the most important element in a picture. It's not.
What making photographs is 'all about' is
everything you can see in the frame/screen/viewfinder. Light, shape, gesture and more.... And each element is as important as the next. That's what a Photographer knows.
Saying that without light you wouldn't see any of that is just being silly.