Lol, who says something like that to someone? Gym teachers, their motivations and their thought processes, will always be a mystery to me.
You may be making this too complicated by assuming they are actually capable of thinking. I never met one who was, anyway. In fact, I don't think I had one who could even get my name right, no matter how many times I told them (and it really isn't that hard).
*Ball thrown at head, calls out unfamiliar name, I look around, mystified, for said individual - BAM!*