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.
Sounds like engineering excellence to me.
But I agree with you that there should perhaps be some kind of physical block/switch built in.