2. A lot of people are like you in disdain for this book
I didn't read it until I was 19 or 20. I definitely disliked the negative worldview expressed, but I also could identify with the sense of wanting to rebel against all the conventions and hypocrisy around me.
My daughter was 15 or 16 when she read it and adores Holden Caulfield. She read it for a variety of reasons--not the least of which was to understand what in it might have driven John Lennon's killer. She is an unabashed John Lennon fan which makes her papa proud. Of course, she's also a big Nirvana/Kurt Cobaine fan too.