Why should it matter if the camera is indoors, in a common area? If you disclose it on your listing and the guest still books your place, then they are aware you have cameras and know where they are. If guests do not want to stay at a place with cameras, then they should book at a place that doesn't use cameras. There are plenty out there. Airbnb shouldn't be telling hosts how to secure their properties.
Even with a policy that bans indoor cameras in common areas, you still will have perverts hiding cameras in their homes.
My house is a former monastery. We rent the rooms out. We have cameras in most public spaces. Mainly front and back door lobby, fire stairwells and hallways. Its like a hotel. But we don't have them in their private rooms. However, we are told we have to take them out. Airbnb is not our only STR platform. So before I remove them, I will stop using their service. if that's the game they want to play.