It is about the feeling of being monitored (and eg not trusted). A camera can also be used to punish you for being human (eg falling asleep for a second... Stupid example) instead of being a machine like your contract expects.
This argument is the same one why nobody should be scared of a police search since you have not done something wrong. It is a consequence of privilege.
The difference is that a camera can only see what another person could see if they were to observe you. A search will also see things that you didn't expect other people to see.
This argument is the same one why nobody should be scared of a police search since you have not done something wrong. It is a consequence of privilege.