I guess I must come from the future, when people finally realize that incidents like this cannot be so simplistically explained away with "the girl lashed out as a result of bullying - it's really someone else's fault she stabbed 8 kids".In what century do you come from? That used to be what was happening in those upper class English public schools in the 19th century, where newcomers were sytematically bullied in order that they could develop this English 'stiff upper lip'... so that they could face the enemy standing at attention in battle order without flinching and showing emotion in front of the troops. What they produced instead were psychopaths and generations of sexual deviants, obsessed with being caned by mistress. Bullying also teaches people that the law doesn't apply to them and they can do it in adult life.
Bullying often leads to physical interaction. Just touching someone without their permission is criminal assault, but is hardly seen like that in schools. People have a right to carry out their activities without being assaulted and harrassed. That includes school too. People get picked upon because of their differences, and they get picked upon by people who gang up together. There were probably warning signs and teachers should have spotted them. But too often, bullying gets written off as 'kids will be kids' and notions that kids cannot be evil. Psychopathic behaviour starts in school and will carry out in adult life. The mother, if she had any inkling, is also responsible for not bringing it up with school authorities. Some resort to suicide because they feel they have nothing to lose and have no avenue because the system tells them to simply buck up. In this case, she had probably decided that she had nothing to lose, but was going to give payback first.
Bullying is visible in a school environment, and teaching staff have some responsibility when they look the other way.
Although I couldn't really follow your post, you do seem to have misinterpreted my post as completely absolving bullies from blame or correction. My main point, and the one you don't really address, is that "bullying", in particular verbal bullying, does not excuse every imaginable form of retaliation (and certainly not a deadly assault with a weapon). I think it's been at least a couple of centuries here in western society since a verbal slight could justify homicide. Is that the century you are from?
Yes, children pick on other children based on a variety of differences, and we wish they wouldn't, but they do and they always will. More to the point, so do adults, and they always will, and there's not much that can be done about it. Children have to learn that they will not always be included in groups, that they will not always be treated kindly or fairly, and how to deal with these problems short of inflicting physical harm on themselves or others.
And yes, psychopathic behaviour can take root at any age. But what would you call the behaviour of the girl who did the stabbing? Certainly appeared to be conduct without regard to its consequences. Seems like classic psychopathic behaviour to me. My point is that there are almost always issues to be addressed ON BOTH SIDES of a bullying problem. They may not be the same issues, but they are both problems worth addressing.
We may not be able to completely prevent bullying, but we ought to be able to do a much better job of preventing these sorts of violent rampages in our schools.