Prosecution and punishment likely to end criminal behaviour? It hasn't worked for any other kind of crime, so it seems unlikely that it will work for "sending communications of an indecent or offensive nature", which is what he was actually convicted of. As to whether prison is the best solution for somebody so obviously mentally ill, that's another matter.
No doubt some fibsters will call this censorship and an infringement of his right to free speech. Much more serious though, is that the girl who was mocked after killing herself, appears to have committed suicide as a result of cyber bullying, potentially and in this case actually more dangerous than the crap that this guy posted. Where is the action on that?