The physicist in the group should be classified as a particle physicist, not a structural mechanics expert. That's as worlds different as saying that someone who studies compiler research is qualified to talk about recurrent neural networks.

Your characterization of the Magic Bullet Theory is inaccurate. The error is in not realizing the car was of an unusual geometry (I believe JFK was elevated, and the seats were different widths apart between the front and the back- unusual for cars of the time.) So assuming the car was normal, and all the seats were the same distance apart and the same height, you would need a magic bullet. Applying deeper understanding of the setup of the car accounts for that, reducing it to the improbable bullet theory. That doesn't mean they were wrong, that means they didn't have access to the car to do direct measurements. When the government locks down the evidence (or in the case of 9/11 immediately ships it off to china, before the investigation begins, literally shipping buildings across the ocean to be recycled) it's not the fault of the conspiracy theorists if they come up with wrong hypothesizes when denied access to the evidence every legitimate researcher should have access to.

Regarding "fake film" you seem too be referring to Oliver Stones "JFK" which is not the source of the Magic Bullet Theory, or any of the theories there, it is merely a collection of the theories prominent at the time, and then fictionalized.