And what's more, every school age child now experiences drills on how to hide from an active shooter. That traumatizes children a whole lot more than having a book a library that 99.9% of the kids will never see. Did you see the video of the mom who talked about how her daughter wanted to have her horse become the class pet and how the mom played along with the idea?
But don't restrict the ability for any Tom Dick or Harry to purchase a semi-automatic high powered rifle of war. Because that would be an infringement on MA CONSTITUTIONAL RIGHTS!