I think the point he is trying to make is that people only think they have minor flaws; Stradlater thinks his compositions are bad only because he doesn't use commas correctly, and Ackley thinks he would be as good as the Basketball player who was making half court shots if he had the same build as him.
Ward Stradlater
Stradlater told him.
Holden knew from personal experience that Jane was not sexually promiscuous. But he also knew from personal experience that Stradlater was. Hence his discomfort with Stradlater dating Jane.
Holden's roommate at pencey prep.
Holden thinks Ward Stradlater is the worst slob in "Catcher" because Stradlater is a "secret slob", "you know, the kind of guy who looks so sharp, but you ought to see his razor - it's full of lather and hairs and crap".
Stradlater was a senior at Pencey Prep. He was Holden's roommate
Holden worries when Stradlater returns because he is anxious about how his date went with Jane Gallagher, a girl Holden cares deeply about. He is concerned that Stradlater may have taken advantage of Jane, who is emotionally significant to Holden. Additionally, Holden's insecurities and fear of losing connection with Jane contribute to his anxiety.
Ward Stradlater
Stradlater thinks the composition is not good because it does not follow the assignment instructions. He criticizes Holden for going off-topic and not focusing on the description of a room as he was asked to do.
Stradlater hits Holden because they get into a physical altercation over a girl they both know, causing Holden's nose to bleed. Stradlater becomes angry and loses his temper during the argument, leading to the physical violence.
When Stradlater borrows Holden's jacket, it symbolizes his exploitation of Holden's possessions without considering his feelings or respecting his boundaries. It reflects Stradlater's selfish nature and lack of regard for Holden as a friend. Additionally, it highlights the power dynamics in their relationship, with Stradlater appearing superior and Holden feeling inferior.
Holden is suggesting that Stradlater lacks moral principles or integrity, indicating that he believes Stradlater is deceitful, dishonest, or unethical in his behavior.
Holden is comparing Stradlater and Ackley to emphasize that both of them are quite irritating and insincere in their interactions with others. His description suggests that they share certain annoying traits like being nosy and overly critical.
Stradlater went on a date with Jane and Holden got jealous at the thought of what they possibly could have done! Holden also asked Stradlater to ask Jane if she still keeps her kings in the back row, and Holden doesn't think he did.
Stradlater criticizes Holden for the composition he writes for him, as Holden had written about his own brother Allie's baseball glove and he feels the topic is inappropriate. Holden is very protective of anything related to Allie and he becomes upset and defensive when Stradlater insults his work.
Stradlater and Holden fight over Jane Gallagher, a girl whom they both know. Stradlater goes on a date with Jane, which upsets Holden because he has deep feelings for her and doesn't like the idea of Stradlater being with her. This leads to a physical fight between the two characters.
Jane and Holden were best friends; Holden didn't want her to be mistreated or for Stradlater and Jane to have sex.