In Defense Of Sex, Even If It's Bad

This week Rowan Somerville won Literary Review's Bad Sex in Fiction Award for his second novel, The Shape of Her, and for sentences such as this:

Like a lepidopterist mounting a tough-skinned insect with a too blunt pin he screwed himself into her.

In response, Laura Miller stands up for fiction that can arouse us:

The presenters of the Bad Sex in Fiction Award gleefully seize upon their targets' most outlandish metaphors; Somerville compared a nipple to the "nose of the loveliest nocturnal animal, sniffing in the night." Yet perfectly serviceable, if disreputable, four-letter words risk turning a scene, in the words of one commentator, into something "perilously close to erotica, with its cheapening effect of sexual arousal." And we can't have that, can we?

Well, why can't we? Is there any reason why the literature that makes us laugh, cry and rage shouldn't also, occasionally, turn us on?