Do you think Holden’s loneliness is self-inflicted (defensive) or is he just unable to connect to the rest of the world?
I think Holden’s loneliness is caused by himself. I think the way he views life, which is completely different from other people’s point of view, makes him want to be secluded from society. For example, when he went to a bar and found D.B.’s ex girlfriend, she asked him to join her and, even though he wanted company, he decided to leave. There he rejected company and had to deal with the loneliness he hates so much. He does that because he doesn’t want to be phony and relate to people he dislikes. And may be this type of attitude grew more with the death of his beloved brother, Allie. He only relates well to people that he likes at least close to how he liked Allie. For example he only genuinely likes few people, like Phoebe, Jane, or the nuns he met in Grand Central Station.