In order for young people to receive any education, this censorship should be separated from the curriculum.  All material from each class, starting from kindergarten to high school, can be thought of as offensive to different people.  Offensive material in school can be subjects one must learn about in order to not repeat it, such as racism, or something concerning their own health, such as sexual education.  Children need to understand the real world, which can be offensive at times, so they can be educated and productive members of society.  If you teach a child how the real world is really like, without having the potential censorship that could be detrimental to their education, they will become more worldly individuals.