In The Outsiders, why doesn't Ponyboy like referring to Sodapop as a drop out?

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.