If you close your Mac notebook with a camera cover installed, you might damage your display because the clearance between the display and keyboard is designed to very tight tolerances. Doesn't this sound like an engineering oversight and not a user error? Why are camera covers not just part of the design? My phone camera physically retracts when not in use.
I guess Apple are going to say that they'd rather focus on the security of the OS and computer to prevent unauthorised software from being able to access the camera than on a mostly cosmetic doodad.