Joel included this line to simply say how J.F.K was assassinated in the year of 1963. He says “what else do I have to say” to show how this was a major event that could not be matched with anything else. John F. Kennedy was the president at the time and as he was riding in an open-top automobile he was shot in the head by Lee Harvey Oswald, who was later killed in front of a national television news audience. This assassination was very shocking, hence why Joel did not have anything else to say other than he was “blown away.”
Chubby Checker, Psycho, Belgians in the Congo
Joel includes each of these topics from the 1960’s in one line because they all corresponded. Chubby Checker had a popular song