Why do some people always pooh-pooh popular culture?

When I saw Gangnam style for the first time, it was my kids that introduced me via SNL. Then I started studying up on it and watching more videos, and I developed a huge appreciation for it.

Over Thanksgiving, I gave my parents and assembled guests a fairly significant lecture about all I had learned, leading up to a presentation of several videos. Of course, my father’s reaction was instant and probably predictable. “Oh god!” Then he sniffs derisively.

There are people on fluther who have the same reaction. I suspect they have never even seen the video and don’t know what they are talking about, but it’s possible they have, and have reasoned arguments about why this is beneath notice. What are those arguments?

Not just Gangnam style, but any other form of popular culture that people might show their disdain for. Like summer reading instead of literature. Or tacky wall hangings instead of Monet and Degas. Or even Monet and Degas instead of Van Gogh or Da Vinci. Led Zeppelin instead of Beethoven. John Cage instead of Aaron Copland. Popular or avant garde vs lettered and staid.

Is it necessary to be a snob? To look down on the popular? To deny that it has any worth? Why do people do that?