If you call something sexy "art", porn detractors will cry out that you're making an excuse for it. But there really is such a thing as erotic art, and equating it with pornography simply because part of its appeal is erotic in nature does a grave disservice to that art form.
How can you say that something sexy can't be artistic, and can't have quality above and beyond the trashiest level of pornography? Why is it worthless solely because it's erotic, regardless of its other merits (and lack of demerits)?
Unless you're against sex itself. And if you're against sex, you're against me.