To show darkness you have to have light. You can't cast a shadow if its pitch black.
In terms of black mirror, they show a society devoid of humanity, true. But in most episodes (there are probably some exceptions) it feels like the lack of humanity is not because of technology, but because the world of the show is populated by monsters. As a result, it doesn't effectively show the dehumanizing power of technology.
When watching an episode - ask yourself, would these characters still do monsterous things without the tech premise? If the answer is yes, then its not really about the tech.