Sadly, in watching this video, I think we are dealing with child psychopaths. There was a recent NY Times Magazine article on this subject and these horrible kids fit the bill. These kids are our future...
From what I've read, this is what happens when children are sexualized too early. They become sociopathic/psychopathic. No concern for anyone but themselves and lack of sympathy. But I'm taking a wild guess that the NY Times didn't cover that angle?