Sounds as if your suggesting the story should have a moral instead of being just a dirty turn-on tale.
I think most choose a category then its pretty random just like taking a brightly coloured book off the shelf. What amazes me is the amount of stuff some authors have written. I don't complete what I don't like but move on; sometimes two or three times.
Authors write in the expectation of being read. Its most unlikely they would write on a desert island. Some hope to leave a legacy after death has silenced them forever. Words are our one way of getting at the future we will never see.
They enable the unlovely and the unattractive to enter the realm of desire. Fat unwholesome men, old ladies well past their prime, can in their imaginations be young studs or sex crazed beautiful young women.
But when the chips are down I would rather be popular between the sheets than between the pages.
'Poetry used to be an art form requiring talent and hard work. There were various conventions, such as meter or rhyme or diction, by which a poem could be distinguished from prose, but they have all been abandoned.
Nowadays, most poetry is ordinary work-a-day prose arranged in arbitrary "lines" and meaningless pseudostanzas, and all it takes to constitute a poem is the bald declaration that it is a poem.'
This speaks volumes for me but many modern poets would be very upset.
'Twas brillig and the slithy toves,
Did gyre and gimble in the wabe:
This is nonsense but wonderful and very famous poetry.
An interesting point which could easily be extended. How about husbandlovers ? I think it shows the large difference between men and women in the sexual realm.