Really short summary of this article: Rock bad. Classical good.
Longer summary: Culture is likened to an iceberg: only a small fraction of it, representing today's culture, is above the surface. The rest, representing the past culture that led to today's, can add depth to the visible part if people are aware of it. Unfortunately, today's culture is profoundly ignorant of its roots, and rock is a prime example. Also, it's just not that good.
I enjoyed the piece because it was well written, and because I think the slam on rock mostly misses the point, but I'm unable to say why. I have vague ideas, but my musical ignorance prevents me from thinking the matter through to a conclusion.
Many people here know a great deal about the whole musical iceberg. If anyone reads the article, I'd love to know your thoughts.