This framing ignores the agency of the teenagers who read the books. Do you think the only media in their lives are media that an adult shows them, with no capacity to seek things out themselves?
Furthermore, do you think that buying alcohol to a minor is okay if they can seek it out themselves?
There is no acceptable reason to keep pornography in a school library.
Magnetic poetry can 'facilitate porn use by minors'. I think you work toward a better-defined standard that doesn't pre-empt the rights of other people who don't share your point of view.