In the demo video, their example has someone sharing a photo of "suspicious people" walking around outside their house, and has neighbors commenting "oh no!" on it. Now the police are alerted to this "crime" which may not even be a crime. Anyone who has an account on NextDoor knows the hysteria around a minor event like a car that someone doesn't recognize being in the neighborhood.
The next step is police or homeowner arresting or shooting someone captured on video and posted to this social feed as having committed a crime.
The developers, marketers, SV investors, etc who promote this type of surveillance as a good idea need a course in ethics and reality.