re: Interesting Read re: CIA involvement in "cover-up" of JFK assassination

Yep

At the end of the day, every conspiracy theory eventually arrives at the point where an unsubstantiated assumption must be made in order for it to work. Not one theory, other than the lone gunman, is fully explained by facts in evidence,

In such a case, where assumptions must be made, the only logical move is to believe the theory with the fewest assumptions. That is that Harbey acted alone, essentially the "null" hypothesis here.