Middle-schoolers are going through the greatest physiological changes that humans experience at any time since their first year. Sometimes that means that the brain and the body aren't quite in sync with each other. Your son may be 6' tall, but he wants to play with his Legos. Your daughter may still have the body of a ten-year-old, but she wants to wear as much makeup as a Kardashian.
This can spill over into their reading as well. Your child may be reading at a college level according to all the tests, but you may not want him reading college-level books because you object to the content. My sister once called me, desperate for a list of reading material for her middle school son who had read EVERYTHING that the school library had to offer. I struggled to help her because I knew a lot of books at his reading level, but few that weren't too mature for him.
You (hopefully) received an Infinite Campus message within the last week or two that details some of the texts your child may encounter during this unit. If you haven't yet, please review it. As parents, you have the right to object to material and ask that your child read something else.
We strive to find books that are age appropriate and yet sufficiently challenging for middle school minds. We try to give them books that are high-interest and provide a diversity of views. Reading gives us the opportunity to explore new views and different worlds than our own. We try to prepare our students for life through their reading. If you ever find something objectionable, take it as an opportunity to have a discussion about your family values with your student. They do listen, even when they seem not to.