It's been quite a while since I've read it, so this may not be a fair assessment. But, I fucking hatedThe Catcher in the Rye. I wasn't even required to read it for school or anything, I just did. Perhaps I just found Holden to be insufferable. I think that was the point, but it did not make it a particularly enjoyable or insightful read at all, save for the overwhelming supertext of DO NOT BE LIKE THIS GUY. The part where he hires a prostitute and just cries in front of her really stuck in my mind. That was when it really sunk in for me that someone read this book and decided that Holden's views were so accurate that he had to go shoot John Lennon with a gun for being phony. Almost unbelievable.
I'm curious at what age you read it. Because I first read it at 15 and thought it was the best book ever. I would even recommend it to people for years.
Then I read it again in my late 20s and had the same reaction you did. I thought he just came off as a whiny little shit. I still feel embarrassed that I recommended that book to people for over 10 years.
I remember telling my wife this after I reread it (she was someone I recommended it to) and she was like, "yeah, I didn't want to say anything at the time, but I hated it."
When I was 13 I thought "You go Holden! Tell off all those phonies!" At 18 I thought "This whiny asshole won't stfu." Then as an adult I realized "Oh, poor kid was dealing with a lot of unaddressed trauma."