while I generally highly appreciate your posts and insights on audio gear, unfortunately I think you've missed the mark on this one. What you've definitely established is that you don't care for post-modern art or contemporary art, but "this art is ugly to me, so obviously it's some kind of scam" is not a thoughtful treatment of the subject.
A great deal of modern* (and postmodern, and contemporary) art that doesn't look like much to the casual viewer is actually a commentary on the very things you find objectionable about the art world. However, since it stands as a reaction to features of the art world, or past art movements, it tends to be obscure and inaccessible to anyone that doesn't invest time in studying art history. That's unfortunate but doesn't mean the art itself is snake oil, it's just not aesthetically pleasing to everyone.
There is a vague analogy to trained and untrained listeners here.
Are many critics full of it? Absolutely. Is "modern art" snake oil? Some of it. (Damien Hirst anyone?) But it's pretty clear from this post you haven't really given the topic as much research as you normally do. If you had, I am sure you would not have missed the opportunity to piss all over Duchamp's Fountain.
This post isn't much different than a non-audiophile confidently and smugly declaring: "Anyone who spends over $200 on audio equipment is delusional - I can't hear a difference between my $100 speakers and the $10,000 set in the store, so there isn't one. To me the $10,000 set actually sounded worse. Audiophiles are all imagining things and are fooled by unethical reviewers."
There is a kernel of truth to that statement, but as we well know here, it's maybe half right at best.
IMO the best analogy outside of audio snake oil is homeopathic "medicine" and other alternative health-boosting products. They all produce strong subjective effects via placebo, are pushed by unethical (or deluded) influencers/reviewers, and require their users to deny very basic scientific facts to maintain belief in their efficacy. To my mind they're virtually the same thing. Sugar pills work on your sensation of pain (or whatever) and audio snake oil works on your sense of hearing. Aside from that the only real difference is you don't eat audio products to get their effects.
*The modern period of art ended in the 1970s.