My wife and I recently encountered a similar scenario, here in Gilbert, Arizona, with one of my son’s books he brought home from school. My son is in first grade so the content of the book was not nearly as graphic and provocative as the one your daughter brought home from the high school, but it did have a lot of pictures and words in the book that we did not feel were appropriate for a first grader to see and read.
We approached it in a similar fashion as you have. First we discussed the book with a couple of the other parents in my son’s class. Some were shocked that such a book could be in a first grade class, others thought it was no big deal, and that we were being over protective. After a couple of days my wife asked our son’s first grade teacher if she could schedule a meeting to discuss the content of the book. She approached the teacher in a very courteous, professional, and respectful manner, which I think made all the difference in the world on the out come of the meeting. The teacher had seen the book in the class but had not taken an in depth look at the content. She said the books are supplied through the school district.
After looking at some of the pictures and content she agreed that it was not appropriate for a first grade class, and took the book to the principal for suggestions on what to do with it. The principal was also a little shocked at the content and decided to remove the book from all the classrooms at the school. If my wife had approached the teacher with a confrontational attitude and the teacher felt she was trying to get her in trouble, I believe the outcome could have been different.
The First Amendment does not mean that our kids have to be subject to all the garbage in the world. Everything has a time and a place and it is up to us as parents to determine what is and what is not appropriate for our children. I do not think it is in the best interest of our children to let the school districts decide that. We count on them to educate our children, but we are ultimately responsible for them as they grow and mature into adults, then they can make their own decisions as to what they allow into their mind, and hopefully we have instilled the virtues and values that will help them make wise decisions.
Hopefully my humble opinion and experience will help you with your decision, and the San Juan High School administration will listen to your concerns and take the appropriate action.