They're not, but they should. Professors shouldn't have to build their class around what their students elect to do to their body. Unfortunately they're picking and choosing groups they want to hurt. That's discrimination. If you're going to let one person elect to do something, people will push things until eventually you'll get to a point where people will view things like getting manicures and pedicures or going to the gym as health maintenance and a reason to miss out on class.are they getting as up in arms about things like plastic surgery?