Throughout the novel, Ponyboy expresses his admiration for his older brother Sodapop. Pony describes Sodapop as being happy-go-lucky, handsome, and understanding. Pony even mentions that he loves Sodapop more than anyone he's ever loved before. In Chapter 2, Pony is having a conversation with Cherry and she asks him if Sodapop works at the gasoline station. When Pony tells her that Soda works there, she smiles and calls him a "doll." Cherry then asks Ponyboy why she never sees Soda at school. Cherry's question forces Ponyboy to tell her that his brother is a dropout. Ponyboy mentions that he hates calling Sodapop a dropout. The term dropout makes Ponyboy think of a "dumb-looking hoodlum" which doesn't fit Sodapop's persona. Even though it bothers Ponyboy that Sodapop is a dropout, he still admires his brother for other reasons. Ponyboy does not view Sodapop as being an unintelligent loser, but sees Soda as a fun, attractive, compassionate person.
In addition, Ponyboy is still stubborn in his beliefs. He refuses to accept that Soda wasn't good at school, just as he refuses to accept that Darry had to make strong sacrifices for the brothers. In one particular scene, Soda uncharacteristically yells at Ponyboy, explaining that school was beyond him. Pony assumes that, since he likes school and he likes Soda, that Soda must like school. Part of his coming of age in the story is realizing that not all things are so black and white.
Ponynoy Curtis doesnt want to refree to him as a drop out because that makes his brother sound stupid. The greasers have a rep that they are dumb and stupid but some of them arent. Ponyboy thinks that the term drop out is offensive and downgrading.
Because he views the term "drop out" as a negativew term and doesn't want Soda to be viewed in that way.