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so, no, i dont think this kid was stupidier than most other kids. and yes, obviously the parents have a huge share of blame.
though, i think, because of the increased social importance of the internet this migth happen to any normal child with normal parents (aware of internet bullying).
and the people to blame should be the same as in real world: the parents, the environment (in real life: schools, etc. ; in the internet: websites, etc.) and the bullies, yes the bullies, because they are aware of the significance internet as nowadays and should measure their actions just like people do in real life.