Is it censorship or is it a protection of innocence?

Quite a bruhaha has erupted regarding the assigned reading of Pat Conroy's The Prince of Tides in a West Virginia AP English class.
Those in favor say that the book's graphic description of rape is only one small (though necessary) part of the story.
Those who oppose it say that such a brutal telling of delicate subject matter isn't necessary in a high school classroom.

I have not read the book in its entirety, but I have read the excerpt in question, and I'd like to sandpaper that image out of my brain.
So while I understand the importance of freedom of speech I must say that if the segment I read is typical, I would not want it assigned as mandatory reading. Even in high school. Even in an advanced program.

How on earth did teachers manage to find challenging literature for college-bound students prior to the 1986 publication of this book?
Why does the author of this book need to describe Americans as "teacher haters" and dissenting parents as "know nothings"?

Why do we need to remove every last smidgen of innocence from the minds of our teens before they reach adulthood?