That is the immediate reaction of most decent people that read the story or watch the video. The problem with commenting about how horrifying it is is that it's not a unique observation and therefore not that interesting.

I am really interested in your third point about preventing this sort of behavior. Contrary to what most parents will say, almost all teenagers are capable of this sort of behavior given the right (or wrong) sequence of events paired with peer pressure. The job for us as parents is to teach our children to be aware of negative influences from peers so that they can either avoid or stand out against things like this.

How do we do teach them? Not sure. But we MUST figure it out before they find themselves in situations like this.