Keegan seems to be judging the mechanics of photographic skill and not the artistry derived from it.

The humor is from imagining a robot pan great works because of implementation flaws. "Mona Lisa. Muddy and drab. 2/10"

Nothing really to do with me trying to classify what is/isn't art.

Some photography is presented as contemporary art, some isn't. "Fine art photography" is usually not credible contemporary art. It's often black and white, formalistic, maybe a female nude... I can imagine an AI that only understands formal qualities becoming pretty good at rating it.

What you might call conceptual photography, on the other hand, is "AI-complete". It's as hard as literature to appreciate, you definitely need a full human-equivalent AI. Roland Barthes' ideas of the studium and the punctum start to open up the intellectual depth of that kind of photo.

This kind of project is possibly credible as a rater of formal quality against some ideal norm, maybe stretching to understanding composition in a crude sense. But everyone knows that it's the unexpected but visually compelling feature that makes an image good. (Or alternatively the significance of its content.) Standard strategies like the "rule of thirds" can only produce formulaic images.