It doesn't require one to think that two people who suddenly found themselves under fire, one of whom was actually hit, would not perceive the situation 100% accurately.
You continue to operate under the preposterous premise that people perfectly remember events. In reality, people remember bits and pieces of events and their minds try to fill in the blanks and not always accurately. JBC had no way of knowing whether the first shot hit inside the limo or not. Nellie would have had no indication of that either.
No. I labour under the premise that cases are solved by evidence. People remember important salient details of an event with generally good accuracy. All studies show this. Sometimes a fact is difficult to observe by humans and in those cases:
a. they generally don't mention it unless specifically asked (which means it has low salience) and
b. when asked indicate that they are not sure and/or provide answers that are best guesses and
c. their answers are spread over the range of possible answers.
But when a large proportion voluntarily report an observation of a fact without prompting (high salience) their observations are correct over 90% of the time.
Even without knowing this, the fact that witnesses independently report on and agree on a detail tells you that it is highly improbable that they all mistakenly observed the same event in the same mistaken way. That only happens if the source of the error is not independent of the witnesses (eg. street lighting affecting the colour of something all in the same way).
Later, when they were led to believe erroneously that JFK had been hit by the first shot, they came to believe that.
?? What evidence do you have that these witnesses did not provide their own observation that JFK reacted to the first shot until someone led them to believe it:
Pierce Allman
James Altgens
Cecil Ault
Ernest Brandt
Charles Brehm
Faye Chism
John Chism
Nellie Connally
Bobby Hargis
George Hickey
Clint Hill
Sam Kinney
Paul Landis
T.E. Moore
Mary Moorman
Jean Newman
Gayle Newman
William Newman
Harold Norman
Ken O'Donnell
David Powers
Malcolm Summers
John Templin
Linda Willis
Abraham Zapruder
Of course we can see that didn't happen because we see JBC reacting to the first shot at about Z-164, just as he described.
You keep coming back to this as some irrefutable fact that JBC is turning in response to a shot. We actually have evidence that contradicts that the turn was in response to a shot - Mary Woodward said that JFK's last turn and wave was after she and others in her group shouted and waved to the President and that this turn (which is the last turn, smiling and waving he ever makes) was BEFORE that first "horrible ear-shattering noise". Witnesses reported the first shot occurring when JFK was smiling and waving to his right. We also have at least 25 people who said that JFK reacted visibly to the first shot and it wasn't by continuing to smile and wave. Furthermore, JBC does not even turn his head to his right to look at JFK, which he said he did after the first shot because he immediately thought that JFK was being targeted by an assassin. He does not look like he believes that JFK is being assassinated but I am not a face reader.
You would have us believe he only imagined that he heard a shot and the first shot wasn't fired for another 3.5 seconds.
That comment would only make sense to someone who thinks that JBC's turn to the right at the same time where JFK turns right and starts smiling and waving could only have occurred because they both heard a rifle shot and thinks that anyone who questions that is nuts.
You then add to your silliness with the ridiculous conclusion that JBC was only hit in the thigh by that shot and didn't feel it.
I am not the only one who thinks JBC didn't feel the thigh wound.
Instead, for some inexplicable reason, just two frames after his jacket bulged out, his right arm suddenly flipped upward and back down in the span of 9 frames, 0.5 seconds, and immediately went into severe gyrations when he twisted and dipped to his right. You claim it was at this point that he was turning to see JFK and wasn't struck in the back until Z270.
Whether the jacket bulges out or the front right lapel simply moves sideways as his right arm moves is not something that can be resolved with the image quality of the zfilm.