I think his problem was with your entire comment and smug sense of entitlement to our awe at your awesome powers of hindsight.
1. Its debatable given the fact that EVERYTHING is on facebook, from your school to your gym, that 12 is too young for social media. You're talking about a medium of communication, not a gun.
2. Her parents deleted her facebook and moved her to another school, it's probably reasonable to assume since they went through that trouble that they attempted resolution with the school first - what more would you have done?
3. It's clear that her parents did have a talk with her about bullying and social media. Did you even read the quoted blurb? We're still talking about an impressionable young girl.
I'm not saying that the bullies are responsible at all for her suicide. Still it's silly - and you should be embarrassed to have done this - to think with such sureness and self satisfaction that the complex issue of suicide can solved with laughably simple absolutes like "no facebook would have solved this" or "all you have to do is tell kids about bullying and it'll fix things".
You have a lot of growing up to do man. Suck my balls.