Why Genre Fiction? --Why Not?

Almost a week ago, I quoted a paragraph from Cormac McCarthy to give an example of what's missing from a diet solely composed of genre fiction. But genre fiction tugs at me like the moon tugs on the ocean. Why? Here's as good an explanation as any I've seen:

After all, quite a few literary masterpieces spend much of their turgid wordage being almost as contrived as any crime novel you’ve ever raced through. On page 13 of my edition of “The Wings of the Dove,” Kate Croy is waiting for her father to appear: “He had not at present come down from his room, which she knew to be above the one they were in.” But of course she knew that, knew it so well that she wouldn’t have to think about it; she is thinking about it only so that she can tell us. If a narrative is going to be as clumsy as that, can’t it have some guns?

From "Blood on the Borders," by Clive James.