Hard to say Flock is the worst... There's a lot of competition. I'll throw Toka into the ring.

https://www.techspot.com/news/113395-flock-biggest-investor-...

Yeah strange how this article is almost entirely focused on consumer apps. These examples might be unhealthy for society, but mostly represent (poor) choices for consumers. Digital cigarettes.

Surveillance tech is the opposite: It represents freedom taken away. That is the more bleak future IMO.