The "what" is just as important as the "why" in this. Consider that he's isn't talking about the kind of music that hipsters of his day would discuss (Punk, New Wave etc), he's going on about the most middle-of-the-road, superficial, mass-market pop music. More or less the equivalent of using hard-core foodie terminology to discuss instant noodles in that he understands the form but none of the content. There's even a scene where somehow he gets tickets to see what I understand was meant to be U2 (before they went fully mass-market pop) and he doesn't get it at all, all he can talk about is the singers poor muscle tone and having to be around working-class people.

This might not be so immediately obvious to us now because there has been a trend in music criticism to take "disposable" pop more seriously and discuss it in the way that "serious" rock music writers did. But I think at the time of writing this would have read as much more jarring and as more evidence of Bateman's emptiness.