What does the ending of Black Mirror Season 3 Episode 6 mean?

The woman deleted the message "Catch him" and no longer cared whether the real criminal was found, perhaps because she had despaired of the people. Even if this group of people know the initiator of the whole incident and what people will do out of anger, it can be expected that there is no label of # dead knock #, but this will not solve the fundamental problem. From people's own problems.

In the era of social network, people are becoming more and more irresponsible for their own remarks. Therefore, a tag that follows the trend is habitually used by people to point to a disgusting person. Knowing that this activity can directly lead to people's death, more people join in for no reason and die effortlessly. I didn't know I was the real goal of the game.

People think they are anonymous and safe, at least they think that the screen separates real life from virtual community. However, when our various identity information is voluntarily and compulsorily input into the social system, our position and actions can be monitored, and those who master or steal this information can manipulate us in the dark without our knowledge.

So what I saw was a warning. If people still don't reflect on their rashness and continue to be used and manipulated, similar tragedies will happen.