Your internal model of how Kennedy was actually shot doesn't contain a high-fidelity of the world in which Oswald grew up and went through a series of mental states that culminated with him shooting Kennedy

Well, my model has Oswald in the Marines with Kerry Thornley — aka Lord Omar, of Discordian legend — and a counterfactual in which a slightly more tripped-out conversation between the two would have led to Oswald becoming an anarchist instead of a Marxist; thus preventing his defection to the Soviet Union ....