What's the deal with middle names and assassins? PT ll

Think of all the people famous for killing. They all have three names: john wayne gacy, lee boyd malvo, john allen mohammed, lee harvey oswald, john wilkes booth... etc. I would bet that every single one of them went by two names just like you and me. Then, for reasons only the media knows, they are branded forever with their middle names. Why is this? Is this is so we can dis-associate ourselves from them? Is this so we can tell ourselves "well, shit, my Mark would never kill somebody. He's just Mark Chapman, a Beatles fan. But then one day dude goes nuts and shoots John Lennon hours after meeting him and getting his autograph he decides to return and wait for John to return from the studio. Now dude is Mark David Chapman. Anyhow, just a warning, everyone you know has a middle name. How come nobody ever gave Charlie Manson a middle name? I also gotta notice most of these guys wear eyeglasses too. By they way, on a nearly unrelated tangent... here is a website for a guy who honestly believes that Steven King killed John Lennon under orders from Ronald Reagan disseminated in code. Warning, this is not a gag site... or the Onion. Dude believes this stuff.