1) Because we have the films, and we can see it wasn't that bright. Some of the films are exceedingly dark, such as Jim Davidson's capture of the melee. You'd think it was happening in a coal mine.
2) And, it isn't consistent with the official story, which has it that Jim Leavelle DID see Ruby in advance, and he tried to jerk Oswald behind him- them being cuffed at the wrists and all.
And even though we don't see any of that in any of the films which all contradict Leavelle's claim, there is the Jackson photo for which Leavelle takes credit for turning Oswald. But, I can prove that it is a ridiculous claim. And anyone can test it: All you have to do is handcuff yourself to someone and try to turn the person the way Leavelle claimed to do. And you'll see the result. It isn't this.
Now remember Leavelle's claim. Leavelle claimed not that he grabbed Oswald's pants in order to turn him, but that his hand was there all along, in Oswald's pants, as they were walking along. So, the idea is that when he saw Ruby, Leavelle moved Oswald by virtue of being cuffed to him, meaning that force could be exerted through the chain of the cuff, and by virtue of him having a hold of Oswald's pants. But, either way, it's Leavelle's hand that had to lead the way. Even though Oswald supposedly turned, which is a rotary motion, Leavelle couldn't exert a rotary force on him. The only thing he could do is pull arm and hand back. If Leavelle is the mover, then Oswald can only follow. Leavelle's hand has to lead the way. You can demonstrate this on yourself. So, you take hold of your pants.
And then you pull back to turn yourself. Your pulling hand leads the way.
My hand is practically out of view because of pulling. Leavelle couldn't use his hand to move Oswald without moving his hand the same direction. But, look at him:
Leavelle's hand is essentially in the same location it was before anything happened.
Of course, I am convinced that both arrangements are phony and anatomically impossible. It is ridiculous to think that Leavelle walked along like that, doing that with his arm. In fact, look how short his arm is, from shoulder to hand. How could it possibly be that short? But, it comes down to leverage, and he can't move Oswald without moving his own arm and hand in the direction of the vector of force.
The ridiculous thing about this is that not only can't you get from A to B, you can't even get to A. Nobody could duplicate the image above. And nobody could duplicate what we see in Jackson either. Remember what happened when they thought they could duplicate Oswald's hand in Jackson. Two people tried, experimentally, and they failed miserably. I pointed out the numerous ways they fell short of duplicating the hand in the photo. And the same thing would happen with this. They wouldn't get close to duplicating it. And then, the very idea that he would walk along with his hand in the man's pants in the first place is preposterous. What purpose did it serve? How did it make Oswald safer? Was it going to protect him from being shot? And the very idea that Oswald would put up with it is ridiculous. He slugged Nick McDonald in the theater because he went for his pants. The very second Leavelle put his hand in his pants, Oswald would have jolted. He would have recoiled. We're told that Oswald was not one to curse, but if he was inclined to curse, I should think he would have stopped and said, "What the fuck do you think you're doing? Get your hand out of my pants." It is ridiculous to think that that doesn't cross the line. Cop be damned, that crosses the line of privacy by a long shot.