Picasso was a great artist but also a man whose main readings were the Katzenjamer Kids. He broke off his friendship with Gertrude Stein because she gave a bundle of them (from American newspapers) to his ex-girlfriend and not to him. I doubt he was highly versed in Marx & Engels. In fact, I doubt he cracked a book over it. He was like most artists, he followed the left-wing herd while becoming a millionaire. Stein & Toklas remained rock-ribbed Republicans and were very poor during WWII and were forced to sell many great works of art. Such is life! If you approach art only through a political lens, you’ll miss a lot.
The issue for me, not being an art aficionado, is that it is abstract and therefor becomes subjective; a matter of opinion. I guess that if you are able find two or more people who agree, then that an abstract artist can be “great.”
I prefer a realist like Davinci and Rembrandt. I especially like Davinci because he was more than just an artist but a scientist and engineer. Maybe an Einstein of his time.