When women are drawing and/or cartooning, why do they put so much detail on hair?

With no specific examples of your own it is difficult to offer anything but generalisations. But a google of anime brings up dozens of images all with characteristic large eyes, tiny or no nose, extremely thin-lipped small mouths and sharply-pointed chin with extravagant hair styles, in the case of many of the women they are often endowed with unnaturally large breasts which are shaped more like balloons than breasts. So I wonder if they really do offer anything in terms of anatomy and proportion.

And they do have a hugely complex and polished finished appearance, I can understand why they are visually popular because they are accomplished graphic images. However your statement includes, "looking through my sketchbook and saw some sketches done in an anime/manga style" – so your teacher looked at several images that were NOT anime/manga (I won't guess what), but she saw something in those images that she felt were more developed than your anime/manga. And offered you advice.

You are having a little hissy fit because that advice implies that there are shortcomings in anime.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.