Ponyboy explained that a military or prison haircut serves as a method to break young men from their social class because it strips them of their identity.
What was his view?
Ponyboy believed that his hair was a significant part of his identity. He considered it insulting for his hair to be cut because that would take away from his identity.
Unlike Ponyboy, Johnny was conforming and this is seen in the way he quickly agrees to the ways of life in the military which includes cutting off his hair. He was not like Ponyboy who had strong views about his identity and deeply treasured his hair.