If a person can become a photographer because he's inspired by the beauty of natural landscapes, and wants to capture and share that beauty with the world, then is it any less valid if a person becomes a photographer because he wants to capture the beauty of naked women and share it with the world?
I think that the biblical concept of lust as a mortal sin presupposes that one's disproportionate interest in sex outshines other important concerns in life; and I think that, from an artistic perspective, this is the problem with most pornography, where the goal is to produce a sexually appealing - rather than an artistically accomplished - image. But if your goal is to depict eroticism artistically, then what's wrong with that?
Sex is an uncomfortable topic for many, but it is a part of life, and I feel that it deserves the artistic treatment just like everything else. And it's not like sunsets or wildlife or flower macros or sports or newborns or any other popular genre of photography is any less cliché, or has any less potential for commercialism, than taking pictures of nude subjects (that may or may not be engaged in sexual activity). Yet, as an erotic photographer, I have a really hard time finding like minds among respected art communities.