Certainty exaggerated, however using the nosedive episode as the example, each of the "ratings" are given by people based on social interactions.

Their emptiness in the case of the show is based on the emptiness of the people themselves. I wouldn't be surprised if such a system did wind up being fairly "empty" as you say (see: twitter, IG etc...), but that's a reflection on the users, not the structure of the system.