I don't subscribe to the official story. However....
Given that everyone and their dog had a motive and that there were so many incestuous interconnections between organised crime ,the intelligence community, politicians, the military, the oil business, the police, the unions, foreign interest groups, the media, financial groups, real and phoney religious groups et al. it's a hopelessly tangled web. That was the way America operated at the time - probably not much different today.
I doubt the real truth of it will ever come out in a form that will give a definitive answer that everyone can accept as fact. In the same way that hardly anyone can agree about the identity of the Whitechapel murderer (or even agree that there was only one killer or that he (or she) was ever called Jack The Ripper).
So just like the Whitechapel case most researchers have their own pet theory. The guy in the video is just as likely a suspect as anyone else.