Jack's guilt - something unrealistic? (Spoilers)
Just watched this for the first time, and something was nagging me the whole way through. So much focus was given to the fact that the man who did the shooting was a radio listener. In the film he's famous as being the shooter who was a fan of the radio, and it's treated as an undisputed fact that his final conversation with Jack directly lead him to shoot several people and himself. Jack's words to him when he called the show were even replayed in the news item about the shooting.
But how are the two things related? I've listened to the call a few times and Jack was only telling him, in very colourful language, that this new girl isn't his type. Of course Jack was just playing with him - he didn't even know the man, let alone the girl he was talking about - so how could what Jack said be attributed to the man's actions? And why did Jack, who thought nothing of mocking and humiliating his callers on air, take so much guilt on himself over the man's actions?