That classical music is the highest level of musical culture? I didn't think anybody would need an explanation, it's generally understood. And for somebody who doesn't understand, it would be impossible to explain in words. It's about as subjective as saying that nothing can be more beautiful than nature.
But not all classical music is great or even good. That hindered me for years from listening more to classical music, because I thought that I couldn't understand some works which I listened to. Then I realized some of it is just bad, and there's nothing more to it.