From "The Key", what injustices do the parents see in the education system of Iran? Which restriction is particularly Ironic?

At school all of the girls line up twice a day and mourn the war dead. They stand in single file lines and beat their breasts. Marjane reflects that self-flagellation is a national ritual. Many of the men beat themselves, often violently with chains or knives, to prove their loyalty and machismo. Marjane, on the other hand, finds humor in all of the serious rituals. She leads her entire school in defiance of the school’s principal. They make funny masks for the soldiers and decorate a room with toilet paper for the anniversary of the revolution all of which gets Marjane and her friends into trouble. All of these practices are ironic from a Western point of view. 

The girl’s parents are brought in and the principal scolds them for not educating the girls at home. Marjane says that the reason they are so rebellious is that “our generation had known secular schools.” Marjane’s mother and father become defiant as well. The principal simply tells them that they must obey or they will be kicked out of school. When the principal tells the parents to make sure the girls wear their veils correctly, Marjane’s father angrily tells her, “If hair is so stimulating as you say, then you need to shave your mustache!”