How was Mark Chapman's killing of John Lennon influenced by his belief that he was Holden Caulfield incarnate?

I've read Catcher in the Rye a million times and I can't see how Holden Caulfield would murder someone. And his view of Jesus was pretty much exactly Lennon's view of Jesus. So how was Mark Chapman incensed by Lennon's views on Jesus when he wanted to be Holden Caulfield himself?