It is soothing to read Holden's monologue about superficial people, who act superficially at times. Holden is a teen and when we are young as he is, we do not have the skill to look beneath the superficiality.
This is where the manipulative mentality scores over the over analytical. A manipulative person sees another human as someone who is either useful or useless. He or She admires only what useful people do.This way they over look the superficiality of people. Then they realize a truth that overly judgmental people fail to see.
The truth is, a lot of superficial acting people are hard working, caring and often just don't know how to act natural. They are not to be judged as bad just because their conversation is superficial. Of course such people are boring companions.
But just because a person's speech or writing has depth or is truthful, it doesn't mean he or she is honest, trustworthy and a harbinger of joy. People are far more complex than that.