Where's the quality education in this?

Earlier during the weekend, my youngest sister went home discouraged about the remark of her high school adviser that she should be doing cheering for the senior pep squad. Though my sister can be athletic she can't do all. Her adviser's remark was, "Wala ako kilalang Cruz na di marunong nyan.", referring to my other sister who did cheering during her time and also had the same adviser. She found comfort to her Ate while giving her tips. I am not an educator but advising is another deep form of teaching that molds a student. It is also compared to discipleship like the relationship Jesus had with his disciples for example. I know my sister can do it but comparing her with my other sister is not good. If I was my sister's parent, I would like to speak my mind to that teacher. Our mother is also aware of it but I'm sure she will have something in mind for that.