Huge difference between saying teachers shouldn't distribute the book and it should be removed from the school library. Libraries don't push books by virtue of having them on their shelves.
And again, when you look at the populations getting uppity about this, it's the ones with high rates of teenage pregnancy and STI transmission. Which makes sense. If Suzy only sees pictures and videos online, or has acts described to her by equally-clueless friends, she's less capable of making informed decisions than someone who also saw the terminology and context in a book. (She's also been informed the topic is taboo.)
Not particularly, but it's a moot question. It's not part of her sex ed. It's on a book shelf. We don't ask why The Lion, The Witch and the Wardrobe is an important part of Suzy's anything when we concur with it being available. Same here.
Turning the question around, what's the harm in Suzy going into a library, picking up this book and learning Grindr exists? (Again, in a hypothetical universe where this sequence of actions occurs without her knowing of it already.)
> Reminder that Suzy is 11 years old, not a teenager
"The average age of first exposure" to online porn is 12 [1]. Even if Suzy's parents practice perfect digital hygiene, unless they're raising her as a houseplant, she's going to be exposed to this at a younger age than we were. The choice is whether she gets exposed within a context of information, understanding and comfort, or if she's thrown into the fray in a state of ignorance.
[1] https://wusfnews.wusf.usf.edu/education/2023-05-14/sex-inter...
Note that my argument begins and ends with libraries. I don't really have an opinion on classroom instruction and materials.