2009 NDP Celebration in School

Janice celebrated 2009 NDP in school with a Sports Carnival. She was eagerly looking forward to this event, because last year her team managed to win a trophy in one of the event. She was also very happy that this year I could join her in school. This year, Janice is in the floor ball game. She had been telling me about the practice she had in school during PE lessons.
The only two shots I managed to capture with the camera.

At the end of the game, I praised her for her good effort in the game and consoled her that its just a game, win or not wining its ok. But she seems cleraly disappointed and kept blaming one of her classmate for causing them to lost the game. I reminded her that a few days ago, there was something on TV that says... "winning the game is not important... the most important thing is that everyone had fun in the game...." Suddenly it strike her.... and thus she stopped blaming him..... Come to think of it.... TV does have its benefit sometimes.

During resting time, I came across an episode with one of the mother (lets call her mother B). Mother B was talking to Janice and asking whether she is Student Z, asking her why she called her son stupid. Janice of course denied she is student Z and further told Mother B that her son has been calling everyone in class idiot, stupid, etc..... In this situation, what should a mother respond?

Later, Janice told me the whole story. It goes like this.... Student B took Student's Z's pencil and kept it in his bag. Upon finding out, Student Z called Student B stupid. And Mother B was there to confront Student Z , unfortunately she was not there, and Mother B even go on to tell the other students present that its not right to call people stupid. I asked Janice about her opinion. Being still too young to understand, she only told me its wrong to "steal" think and call people stupid or idiot. The first thing I told her is that : Yes, its rude to call people stupid. But when other call you stupid, you must have done something to make that person make such a remark". Am I right to say this? Any comment? Furthermore, its not right of her to say that Student B steal thing, 'cos she did not witness the whole event. So its not right to judge a person by merely hear-say. But the most important point that I was thinking was "why Mother B did not react when someone told her that Student B go round scolding others stupid and idiot, instead she is only interested in find Student Z whom called her son stupid?" This way of standing up for her son is right or wrong? Can anyone enlighten me?