Who states "They'd never believe a greasy lookin' mug could be a hero"?

In S.E. Hinton’s novel The Outsiders, we are faced with a clash between the poor “gang” of Greasers and their wealthy “social club” counterparts, the Socs. The particular quote above comes from Sodapop’s best friend Steve. Some have criticized Steve for his sustained optimism and believe that his character does not develop the action or outcome of the novel; however, his role is one of balance, as both Greaser and Soc groups have their particular pairings of optimists and pessimists.
To return to the quote: this is actually a portion of a larger exchange he has with Ponyboy after the newspaper publishes a story about Ponyboy, Johnny, and Dally’s heroic rescue of children from a burning church in the previous chapter. An expanded look at the exchange clarifies this point: “Why, he had to get a haircut to get his picture in the paper. They’d never believe a greasy lookin’ mug could be a hero. How do you like bein’ a hero, big shot?" (p. 58).
Ponyboy’s hair had mostly been burned or singed away from the fire, and so Steve makes a reference to the stereotype of scalping among some Native American peoples, which is a way for Hinton to describe the degree of hair missing from Ponyboy’s head, without plainly stating it.