I'm sorry this happened to you
.
I think this kind of thing is cultural, I could never imagine children do that in Belgium for example. I've had dozens of bald(ing) teachers in middle school and high school, or even university, and no one ever called them bald, either in front of them or when they were talking about the teacher in private.
I've been on dates with a few Asian girls, and from what they told me, balding is seen as a curse in China for example, if you're balding, it means you don't take care of yourself (I know, enraging).
Also, Japan? Look no further than their video games or anime, all the characters (except maybe Krillin
) have fabulous hair, no wonder balding is seen as abnormal.