Yeah, someone can't be convicted of a crime unless they themselves committed it. Doing something that may (or may not) lead to someone else committing a crime or accidental death is not grounds for prosecution under general circumstances. This reminds me of billboards along interstate highways. Statistics have proven without question that putting a billboard on a stretch of highway will result in a certain amount of highway deaths every year. However, the fault is still with the driver who allowed themselves to become distracted, not with the advertising agency.
This is one of the many instances where morality and legality don't mix. I can think of many highly amoral things you can do that are completely within legal perameters. Let's say some psychopath gets ahold of a suicide hotline phone list. Then they call each person, yells at them, and dares them to kill themselves. It would be VERY difficult to convict the person of anything, because the final decision and action was taken by the suicidal person, not the creep who called them. I dunno, there may be some laws on the books for very special case scenarios, and I know there are many laws about interacting with children.
But the shutting down of social networks is no different then the placement of billboards on a highway. Yes, we know that it WILL lead to death, but in every individual case, the death can't be blamed on the shutting down of the network.