Misuse of criminal law

Student Found Guilty Of 'Disturbing The Peace' For Sending Nasty Political Email To Professor Techdirt: "Student Found Guilty Of 'Disturbing The Peace' For Sending Nasty Political Email To Professor" (TechDirt, 18 June 2009)

How sending an e-mail can breach the peace, I am puzzled. It was not a collective e-mail, say to the whole of the University, what would have justified (maybe) the analogy of the public forum. At most, the e-mail, if repeated at least once, would fall within harassment, but certainly not breach of the peace.
Disciplinary actions might also be foreseen if the university charter of conduct was breached