The teens who harassed her should be charged with harassment (or perhaps even an up-scaled version that includes some sort of assault). But ultimately, she is responsible for her own death.
Clearly, "growing thicker skin" isn't the only solution. But internment camps for people who hurt others "feels"? That's retarded. Yes, people should be taught to not bully others and yes, bullies should held accountable (via harassment laws). But people also have to at least try not be excessively oversensitive pansies. And the only thing I did every day was "grow thicker skin". Right up until I was big enough to fight back. Because when I was growing up, "bullying" included getting the shit beat out of you along with the verbal assault.
I mean, you can make legitimate arguments for what you're trying to say if you compare something like daily verbal abuse to a getting slapped once in awhile. But when comparing cases of equal severity, physical abuse will always be more serious because the victim has no control over physical pain. They can, however, mitigate their own "mental anguish", at least to some degree. It's a bit of an absurd analogy, but it's like comparing "assault with deadly words" to "assault with a deadly weapon". You can ignore the words.