I did not respond, but the invitation made me think. Maybe we can trace this to primitive origins of hearing. Classical music appeals by its sounds to our emotions, and by its structure to our perceptions of order. I speculate that hearing and internalizing classical music's structured complexity reinforces our ability to perceive structure in life's complexities. I'm not sure I want to go there.
Musical beauty is harder to judge, residing as it does in the beholder's ear and cultural bias.
If I may judge beauty by emotional effect, then much modern music seems ugly to me. Perhaps many thoughtful composers, shocked by two world wars and countless other modern barbarities, can write only chaotic, barbaric music. I give thanks for Leonard Bernstein, Aaron Copland, and other inspiring exceptions to this dismal rule.