Jews lack creativity and originality. In their minds, art is just "random shit" that you can make up and call "art", and it counts as "art" if you shill it hard enough. 
He actually , nonironically thought that he was being artistic and special (and then could tell his friends that he got away with serving a shoe as a piece of art because that's how jews work). 
These things happen all the time with jews, they are not accidents, they are actually a nice insight into their souls.