What are we to make of this event – rightly or wrongly, the most intensely-studied event in U.S. history – fifty years after the fact? On first glance, the assassination and its aftermath are a historian’s dream: millions of pages of testimony, thousands of eyewitnesses, multiple autopsies and ballistics reports; there’s even a Kodachrome film that frames the event down to the fraction of a second. Yet I can think of very few details from that day, even small ones, that remain completely uncontested by either buffs or scholars. I’m not sure this can be said about any historical event, even 9/11. Within three years of the assassination, 200 books had appeared; the bibliography is now well over 3,000 even without counting films, documentaries, blogs and newsletters. Finally, a very strong majority of these sources are saturated with conspiracy thinking. American citizens still mutiny against the official account that pointed to Lee Oswald (as he was known then) as a “lone gunman.” And to my eyes, a vast percentage of those focus on a single type of conspiracy, from both right and left: that a coup d’état robbed our nation of more peaceful and prosperous future.
It eventually became big business. No relatively routine murder case, apart from who one of the victims was, has had so much written about it.
In the end, there was NO mystery at all.
Hofstadter's classic essay is here.