Bill, I enjoyed your post, it is well-thought and incisive. The more I think about it the more I think you are right. I do not want to enter in the correct way of interpreting Bresson, it suffices that what you are saying makes sense to me. Your analogy with rifle shooting is a good one and it made me think of another one (closer to my interests): It's as if the compositional elements of the photo are words chosen aforehand in random order that when combined properly express a meaningful sentence. Notice how it is possible to end up with two different meaningful sentences out of the the same string of randomly ordered words (if we want to be precise we must say that it is even possible to end up with two or more different meanings even if we use the exact same string of words, e.g. "Mary had a little lamb" may mean two different things). Now, photographers may recombine the very same compositional elements in different ways so that, although starting with the same constituents they end up with a different composite structure. That makes sense too, for two photographers in the same field may produce surprisingly different images of the same event.
Does that mean that the event is actually a different one for each photographer? I do not think. The images are different but the event is one.To give another example: Suppose two photographers take a picture of an elephant in a zoo. Their angles are different, the equipment is different, the backgrounds are different and so on. The pictorial output results in two (perhaps strikingly) different photos - but of the same elephant! That is to say, each photographer is responsible for the pictorial represantation of a given event. It wouldn't suprise me then if it were possible for two photographers to take a picture of the same event and end up with two different, perhaps unrelated Decisive Moments photos. Some time ago I watched a documentary where this precise point was made. Kapa and Bresson were taken photos of the same rally and they ended up with completely different photos, each of which (a) documented the same event (b) commented on it in a different way.