There is a difference between believing something is true based on some of the evidence, and a belief based on no evidence while being confident that the contrary evidence cannot possibly be true. The first is just a difference of opinion about which evidence is more reliable. The second puts you in la-la land.
When do you believe JFK was hit?
When do you believe JBC was hit?
Since eyewitness/earwitness testimony is notoriously unreliable (especially in a virtual echo chamber like Dealey Plaza), how does the Zapruder film, and only the Zapruder film, support your beliefs as to when JFK was hit and when JBC was hit?