I can understand the delayed or non-response by many folks to the shots. A quick, sudden, unexpected event that was over before many realized what was happening. Interpreting movements in the crowd, though, is something different and subjective. I think anyone with a theory could look at the grainy film images and find bystanders who they believe support whatever narrative they want to reach. I don't find the "head snaps" to be unmistakable or clear. It's interesting but not compelling. In contrast, I think the witness testimony that they were three shots is compelling and supported by the evidence. Almost all these witnesses suggested the shots came from one location - although they disagreed where. That means one shooter firing a maximum of three shots. That alone undermines many CTer theories about multiple shooters.
I agree completely. So how were the witnesses reliable when it comes to the number of shots but not reliable as to the pattern of the shots, the rapidity of the last two shots, where JFK was when the first shot occurred and how he responded to it?
And all of the evidence that is being rejected as unreliable all fits together: the shot pattern with the last two close together requires JFK to be hit by the first shot. The estimated 2:1 ratio recalled by several witnesses would mean the first shot had to have occurred just before JFK is seen reacting when he emerges from behind the sign, which fits with the witnesses who said that JFK reacted immediately to the first shot.
Perhaps, the more important question is: how is it that all these witnesses were mistaken but in a way that the mistakes are all mutually consistent?