For me it’s the paranoia surrounding webcams. People outright refuse to own one and I understand, until they go on and on about how they’re being spied. Here’s the secret - unplug the damn thing when you think you won’t use it or haven’t used it in a while.
They, whoever it is, can’t really spy on you on something that’s already off and unplugged!
Sorry if I was wrong about the prevalence of such protections. My perception may be biased because the notebooks used by our company are all equipped with a switch or shutter of some sort. (HP brand, IIRC) Regarding your second point, however: surely a shutter physically obscuring the camera lens is just as effective as disconnecting the camera when it comes to protecting the user’s privacy?