There's a difference between “talking about sex” and “pornography”.

> So they made their father drink wine that night. And the firstborn went in and lay with her father. He did not know when she lay down or when she arose. The next day, the firstborn said to the younger, “Behold, I lay last night with my father. Let us make him drink wine tonight also. Then you go in and lie with him, that we may preserve offspring from our father.” So they made their father drink wine that night also. And the younger arose and lay with him, and he did not know when she lay down or when she arose. Thus both the daughters of Lot became pregnant by their father. (Genesis 19:33–36)

> Your lips drip nectar, my bride; honey and milk are under your tongue; the fragrance of your garments is like the fragrance of Lebanon. A garden locked is my sister, my bride, a spring locked, a fountain sealed. Your shoots are an orchard of pomegranates with all choicest fruits, henna with nard, […] Awake, O north wind, and come, O south wind! Blow upon my garden, let its spices flow. Let my beloved come to his garden, and eat its choicest fruits. I came to my garden, my sister, my bride, I gathered my myrrh with my spice, I ate my honeycomb with my honey, I drank my wine with my milk. Eat, friends, drink, and be drunk with love! (Song of Solomon 4:11–13, 4:16–5:1)

> How beautiful and pleasant you are, O loved one, with all your delights! Your stature is like a palm tree, and your breasts are like its clusters. I say I will climb the palm tree and lay hold of its fruit. Oh may your breasts be like clusters of the vine, and the scent of your breath like apples, and your mouth like the best wine. It goes down smoothly for my beloved, gliding over lips and teeth. (Song of Solomon 7:6–9)

> Yet she increased her whoring, remembering the days of her youth, when she played the whore in the land of Egypt and lusted after her lovers there, whose members were like those of donkeys, and whose issue was like that of horses. Thus you longed for the lewdness of your youth, when the Egyptians handled your bosom and pressed your young breasts. (Ezekiel 23:19–21)

— The Holy Bible (ESV) (famously not pornography)

And a honourable mention to the KJV translators, who – when faced with a double-meaning – took the literal translation:

> My beloved put in his hand by the hole of the door, and my bowels were moved for him. I rose up to open to my beloved; and my hands dropped with myrrh, and my fingers with sweet smelling myrrh, upon the handles of the lock. (Song of Solomon 5:4–5)

Idiomatically, “my bowels were moved” in the original Hebrew refers to a strong emotional response (ESV translates it as “my heart was thrilled”) – but considering the rest of this book, I have no doubt that the wordplay is intentional.

A book doesn't become pornography, just because the authors chose not to censor all references to / descriptions of sexuality. I understand keeping these books out of the hands of 6-year-olds, but by the time they've reached the age where their own minds are generating sexual material, I don't see the benefit of denying them a safe environment to explore such ideas (i.e., books). Most teenagers have more pressure (from their peers) to engage in actual sex than to read a particular library book. So… what happens when they're not aware of sexual consent, safe sex practices (e.g. condoms aren't just for contraception), or any kind of role model? (Hint: some effects are visible in the statistical tables.) I'm not sure what these bans are supposed to accomplish, other than make parents feel better.