Many videos now contain everyday video backdrops. I saw one the other day that was just chickens wandering around. I'm sure they are there to prevent copywrite bots from discovering IP theft. That is just my best guess though.

Possible that the videos themselves are from hacked iot devices, or the protocol transfering data going from the camera towards the servers might not be encrypted so someone intercepts their data :( But wandering why in the world would someone point a camera at families ?