So, you have no problem with teaching showing snuff films, and child pornography to 2nd graders. I think that using discretion in books and other media used in schools is a far lesser problem than failing to do so. Censorship requires authoritative (governments, Catholic church and many others can be cited) agencies banishing or restricting objectionable content -- with associated civil or criminal penalties (official or not) associated with violations -- without penalties, there is no real restriction. Lessor restrictions are really not censorship, that though may well be undesirable or even odious and evil.
Say I personally kill you for reading the Bible because I think it is evil -- this is not censorship.
Say Muslims are known to kill people for reading the Bible because I think it is evil -- this is not necessarily censorship, depends on whether said Muslims are extremist that are officially or unofficial sanctioned or tolerated, if so -- yeah its censorship, otherwise it is same same as me doing it.
Being a member of the school book and saying a teacher crossed the line by showing Debbie Does Dallas to 2nd graders crossed the line and make sure she gets fired is not censorship, it is reasonable because community standards dictate that such would be totally inappropriate content. Showing Debbie Does Dallas to seniors is almost certainly the same answer -- it is not the in the purview of the school exercising its in loco parentis rights and responsibility to educate students in such a manner. Minors do not have the same legal rights as adults. See Contributing to the delinquency of a minor if you still doubt the responsibility to exercise judgment.