As a mother of three I completely understand that it is good to give children the tools to deal with these situations themselves. That said, it sounds like your email was perfectly acceptable. You were not asking her to punish the "bully" and, in fact, hoped the teacher could use this incident, without naming names, as a lesson for the entire class. What the teacher did next was ridiculous. After learning about the teacher's response, I would have written her another polite email asking this question: "If my husband, your peer, sent you an email saying, 'You think you are so smart. You're not. You are ugly and nobody likes you,' would the school principal have thought it proper to make you and my husband, the bully in this hypothetical example, sit in a room until you could be friends?" I would have cc'd the school's principal and the superintendent of schools on this email.