If the doorbell camera was facing into the outside, then I am not sure what grounds the tenants have to complain. Hotels and apartments can and do monitor public areas.
Is there some sort of law or rule obligating tenants to keeping the view of cameras unobstructed?
If that's the case then merely standing in view of the camera would qualify as vandalism as well because you'd be obstructing the view of what is behind you.
https://www.airbnb.com/help/article/887/what-are-airbnb-s-ru...