If i had a security system with a camera, I would want to have the ability to erase any video that I did not want to have around. A system that backs up to the cloud that does not give the system owner the right to permanently delete all copies is problematic.
Once there is a court order, that’s another kettle of fish. But unless there is a court order, the system owner should be able to delete anything he damn well pleases.
Deletion of video, after an incident, could be taken as an attempt to destroy evidence. Plus, the video might still be recoverable.