This is a site on religion. And so the accepted references include mostly Hindu scriptures which include Vedas, Vedangas, Upavedas, Upanishads, Smritis, Upasmritis, Puranas, Itihasas, Tantras, Agamas, Darshanas etc.
We also accept the works of Acharyas (like say Adi Shankara) who are/were well-versed in scriptures and works/sayings of saints/Yogis (like say Ramakrishna Paramhamsa) who have direct perception of truths.
Now, KamaSutra is not a religious text. And, that's why it is not an accepted book to cite here.
Any text that is written by a Hindu, and which is written in Sanskrit does not become a valid reference to cite here.
Take for example the great poet Kalidasa and his works.
Those works are literary works of the highest order in Sanskrit. The contents also are sometimes fictional versions of stories which are found in Hindu scriptures. The content also is not objectionable like it is in case of Kama Sutra.
But still such works are not accepted here to be cited as references. Then how can we accept a book like Kamasutra which is not based on religion?
Regarding Kamashastra then I have seen few verses from one such text in one of the Tantra books that I have. But that is a scripture. The verses there, like any other Tantras, are spoken by Lord Shiva.
Those verses deal with sexuality alright but they are not sexually explicit and pornographic in nature as is the case with Kamasutra.
So, bottomline is, since Kamasutra isn't a text on religion and this is a site on religion. it can't be accepted as a valid reference here.
Another thing to note here is that the nature of our site is such that those questions which can be answered only by citing Kamasutra as reference will be closed as off-topic. And, that's why we have till date only two such answers which use the text as reference.
