In chapter 5 of "The Outsiders" Johnny and Ponyboy are on the run from the police because Johnny killed a Soc while trying to protect Ponyboy. Johnny decides they need a disguise. He buys peroxide and tells Ponyboy he must cut his hair and dye it blonde. Ponyboy has a big problem with this. He tells Johnny he doesn't want to cut his hair because it took him a long time to grow it just the way he wanted it. He is very proud of his long hair and he doesn't want to change it in any way. He finally agrees and Johnny cuts Ponyboys hair with a knife, then Ponyboy cuts Johnny's hair.
The long hair of the Greasers is a symbolic representation of who they are and what they stand for. Ponyboy does not want to cut his hair because it is all he has left of the life that they have left. He believes that it is the hair that makes him who he is, a Greaser. The long hair of the Greasers is part of the theme of judging others. It is through much inner thought that Ponyboy finds that there is more to people than the obvious. This is one part of the novel that supports S.E. Hinton's theme that people may not be what they seem.
Because ponyboy does not want to cut and dye his long greasy hair.
Pony Boy has a problem with Johnny’s disguise idea because he doesn’t want to cut his hair that he took so long to grow and that it symbolizes that he is a greaser.
because he doesn't want to lose his hair and not look "tuff" anymore