Well, what can I say? This doesnt surprise me at all. Rather, I'm surprised the kids aren't more actively punished for their appearance (however natural it may be).
My school I guess is pretty relaxed compared to these places. Kids can dye their hair as long as it's a variation of a korean'esque colour. Some kids go around with redish hair, brownish hair, and even one kid dyed his hair actual-black (as opposed to the natural very-dark-brown Korean colour). Also, if you have a "reason" to have long hair, somehow this legitimizes leniancy. The kids in the school rock band and the magician are allowed longer hair because of "performing!" (the answer one kid gave).
But a growing trend, more popular than a monk-cut or a military-cut, seems to be a preference by the teachers for the kids to have a mushroom-cut. Yes, that's right, the atrocious 90's mushroom-cut. ...I love that the kids call it a 귀두-것 (Head-of-the-penis-cut) hahaha. They're aware of the ugliness.
An introduction written by a student (I kept it cos of the awesomeness):
"My hairstyle is look like mushroom and I don't like this hairstyle. Would you join me? If you cut your hair like me, I'm happy."
(exceptional english skills if I do say so myself)
Anywa, I got off topic...
Where was I? Oh yes, Koreans are kinda stupid.

They just don't know that people look different from one another. Nothing shows this more than looking at class photos.