Pedestrian, in regards to music as a way to attract mates, that doesn't mean men will only play music in order to attract females. In essence, what it means is that evolution has rewarded men who were musical with higher fitness because females found them more attractive. Them actively pursuing women with music could (or would) of course be a strategy, but it doesn't have to. Thus, despite the quotation, I doubt the guy seriously means men only play music in order to attract females, but rather that music has the place it has in culture today because of it's related fitness benefits in our evolutionary history. On average, musical guys had more kids, regardless of why they performed (and remember this is way back then when they probably didn't have bands and go on tour). In this situation, it would still be likely for men to develop a general strategy serenading women of course.
It's just hard to formulate it perfectly in the space of a sentence.
As for what I believe, I believe music has piggybacked our capacity for communication. Our ability to vocally communicate has increased and our capacity for music with it. At some point, when music has been discovered and spread through a population, music itself could be selected for and so then it could go from being merely a "spandrel" to becoming an adaptation in itself, just like birds have specialized wings adapted for various forms of flight. When or if that ever happened, I don't know .. I guess I'd want to read a book or see a lecture on it before making up my mind about it!
edit :
As a side note, I'm sure if song birds had ever become as intelligent and culturally advanced as people, they would like music too
