I think that the quote of which you speak is located in Chapter 17. Holden is giving his opinion about the very nature of phoniness that exists at a Boys' school, and in the process reflects how he, himself, does not belong anywhere. It is a quote that is reflective of many elements. The first is that Holden has a very distinct view of the social setting of school, and adolescence, in general. Defining socialization through the deliberate use of the word "clique," Holden defines the process by which people socialize as one of division. In "everyone sticking together," Holden also brings out how there is little in way of social diversity and interaction. Holden brings out how there is only separate monologues, and not true dialogue. At the same time, there is a bit of longing in his assessment because as he criticizes everyone "sticking together" with their own clique, there does not seem to be any domain that includes him. There is a note of bitterness in this light, bringing out the complex relationship Holden possesses towards how social constructions are both made and his association with them.