What I learn from Carl Wilson's Let's Talk About Love: The Journey to the End of Taste:
1) Different people--with different cultural backgrounds, different levels of income and education, etc--will like different things. There's no need to be a snob about it. Besides, if you put yourself into it, you can find the intellectual merits of liking anything, whether it's Celine Dion or Kraftwerk.
2) In time, camp can be cool.
3) There's no such thing as "highbrow" and "lowbrow" in the West before the end of 19th century, just like there's no difference between public persona and the private self. (The "self" is a relatively new concept.) As the bourgeois became richer and more "upper class," they felt the need to set themselves above the rest, kicking the working people out of opera houses and confining them to music parlors.
4) Music can serve various purposes. It can give us a glimpse of the sublime, offer life-affirming (or life-negating) messages, become the soundtrack to our day-to-day activities. So, it's only natural that we have different kinds of music. But of course, it doesn't necessarily mean that a certain kind of music is superior to the other. (It's like this: not all questions need to be existential questions; sometimes you just need to ask simple question like, what time the next bus will come.)