It's good that many schools have changed their policies, but I didn't even know this was a thing. 
m-en.yna.co.kr/view/AEN20210824001000315
South Korean schools' strict dress code policies, which had been implemented to strengthen students' focus on academics and create uniformity among peers, have been at the center of criticism in recent years for harming students' privacy and breaching their basic rights, such as freedom of expression.
In May, a civic youth group Asunaro filed a petition to the National Human Rights Commission of Korea against 33 elementary, middle and high schools in Seoul for restricting students' rights to choose their own hairstyles and clothing. The number represented about 2.5 percent of the 1,316 elementary, middle and high schools in the city.
Those schools had rules banning their students from going to school and back home in training suits, having their hair permed or dyed, enforcing all-white underwear for girls or regulating the color of socks and stockings in spite of the city council's almost decade-old student human rights ordinance, according to the group.