I think genres are still valuable, although admittedly they can be somewhat obstructive from time to time.

As for eclecticism, it has nothing to do with prejudice. Eclecticism is about taste, and there can be no prejudice in taste, as long as the taste is honest. Neither does disliking a genre have to mean prejudice. For example, I'm not particularly found of the country genre, but I do have the common sense to add to that: in general. I can name several country artists that I love, but I know that I tend not to like the majority of country music because of its general sound. I still give country artists a chance, or five chances.

Where prejudice comes in is when you dismiss (or for that matter, decide you like) a song based upon any category it may fall into, or an array of songs based upon your experience with a subdivision of it.