Kids these days are just early versions of people these days. What's wrong is we lack a robust Church to guide us (as a people).
People who have no fear of God....have no fear of man. They do what they will.
They do not learn compassion, to love each other, to serve each other, to forgive each other.
Yes, I agree it is the violent games (they admitted to doing this in order to please "Slenderman"....however, had they been taught the love of God, they would not so easily have been influenced by a game.
In this case, it might be the child is a sociopath, however, in general society is becoming "me" focused, versus "them"....and that is the start of the end.