And this exact same thing didn't happen before facebook? Before the Internet? Are you out of your mind?
Kids -can be- freaking dumb.... they don't fully understand the world yet and what their actions actually mean. Hence, the term kids. How much have you changed and realized from 14 to 30, to 40, to 50? Every day now (I'm in my early 30s), I deal with something that I would have handled differently as little as 6 months ago.
Facebook is not the problem. One could argue it's the parents problems for not "raising" their kids properly and to some extent I would agree. However, think about what you did when you were a teenager. Did you ever lie to your parents and say you were going to your best friends house for a sleepover while you were really going to a party to get drunk? I did. If you were a happy, successful kid, why would you parents not believe you? I exploited that in my parents and most of us have.
This is a sad, sad story. I hate reading about stuff like this. But this is not FB causing problems. If FB did not exist, a simple email with the video file to the entire school does exactly the same if not even more damage. If the Internet didn't exist, a USB drive would have gone around the school. End result? Same.
Blame FB if you want, but you're dumb.