Good for you. I love it when liberals tell me you can't define art. I shoot right back at them with Ayn Rand's definition of art.
Art is a selective re-creation of reality according to an artist’s metaphysical value-judgments.
They never know what to say. They've always been taught that art is undefinable and that, therefore, anything must be accepted as art. It never occurred to them you could actually nail it down.
Funny how the old-timers (ya know like Leonardo and Michelangelo) knew what was good and what stunk. The idea of rebel art and art in conflict with the establishment/religion is a modern idea. When it works, it works. When it fails, it’s bad art.