Holden's opinions and judgements serve to isolate him. These judgements are certainly drawn from and/or characteristic of his own frame of reference.
We can see how Holden separates himself from the world in this way here, when he is describing how people think he acts younger than his age.
"It’s partly true, too, but it isn’t all true. People always think something’s all true. I don’t give a damn, except that I get bored sometimes when people tell me to act my age. Sometimes I act a lot older than I am—I really do—but people never notice it. People never notice anything."
Holden's rather extreme opinions are expressed throughout the novel and often serve to create and define the divide that he perceives between himself and others. Holden's repeated condemnation of people as "phonies" is one of the stronger manifestations of this habit.
“You ought to go to a boys’ school sometime. Try it sometime,” I said. “It’s full of phonies, and all you do is study so that you can learn enough to be smart enough to be able to buy a goddam Cadillac some day..."
Instances where Holden expresses the opinion that someone is a phony occur often in the text and can be used as quotes to suggest that Holden's own frame of reference is based on a divisive taxonomy/categorization, where people are divided into two groups: honest and phony. There are very few people standing with Holden on the honest side of the dividing line, according to his own thinking.