When my older brother was ~12-13, the only books he would read were Stephen King books. He'd hole up in his room and read one in its entirety over a weekend. While my parents weren't necessarily thrilled about the subject matter, they figured it was better than not reading at all.
My Jr. High honors English classes offered some relatively
risqué
books as suggested reading, but there were always alternatives. IIRC, when I chose to read
The Catcher in the Rye in 8th grade I was required to have my parents sign a form indicating that it was okay with them. Perhaps I was spoiled by parents who were actually active and involved in my education, but I don't recall ever reading anything K-12 that they were unaware of.
I think parents have a legitimate right to object if a child is
forced to read material that is deemed outside of their chosen standards. If, however, the child
chooses something off of a larger list (which is how I'm reading this), it sounds to me like a matter to be dealt with at home through open and honest discussion, not one to be taken to the streets screaming for the teacher's head.
It's symptomatic of our society's tendency to ignore and then overcompensate to prove how passionate we are once something is brought to our attention.