I have never believed that a big conspiracy could have been kept quiet. I believe Oswald fired his gun and hit the president. But I wouldn't be surprised if the mother of all coincidences occurred and there were TWO discrete shooters there that day. It's a very simple conjecture that would satisfy a lot of the "what about this" mumbo jumbo.
It's like a Rorschach test. You take a grainy underexposed photo of some bushes and look for something meaningful. Since the human brain excels at seeing patterns, even when they don't exist (ie. the tendency to see faces in all manner of random images), you can likely find something.
In the case of "Badgeman" it was helped along by some artificial coloring in to make sure you see the patterns they wanted you to see.
That was Gary Mack, who is generally level-headed guy and was sincere at the time. I'm not sure if he still stands by "Badgeman".
As for the soldier, Gordon Arnold, he was a crank that wasn't even there. See: http://mcadams.posc.mu.edu/arnold1.htm
One thing about the Kennedy case that complicates things for the casual reader. You've probably heard that in notorious murder cases it is routine for the police to get false confessions from people that just like the attention. Imagine how much more so that would be in the case of a presidential assassination where there has been a ton of popular literature creating hundreds of various theories. The case is filled with false confessions and false witnesses. People who voluntarilly came forward and claimed to see something, be somewhere, or even be involved, that were simply making it up.