So, why was James Bookhout picked to play the role of Jack Ruby? Isn't it obvious? It's because they thought he looked enough like Jack Ruby to get away with it. That was the most important thing.
And Jack Ruby didn't go along with it. He didn't know he was being framed. Oswald knew that he was being framed, but Ruby didn't. Ruby was tricked. He was duped. He thought the Dallas Police were his friends and would never lie to him. They told him that he shot Oswald, and he believed them.
Backes, it is absolutely certain that that short pudgy guy wielding the gun was not Jack Ruby.
And it is absolutely certain that these two are the same person separated by the passage of 26 years of time.
The Garage Shooter was definitely FBI Agent James Bookhout. You would think that by the year 2017, people would be capable of being rational. But then again, this concerns the JFK assassination, which is a Bizarro World, devoid of all reason and rationality, and populated by fire-spewing ghouls.