He was killed by Oswald because Oswald wanted to prove to his Cuban & Russian pals that he was indeed the American Che. Mostly Cuban pals the Russians by then had pretty much washed their hands of him.
Every other reason is pure fantasy. Those fantasy reasons misdirect Oswald’s ties to Cuba to it’s advantage and continue to do so to this day.
I don’t disagree that Oswald fired the round.
It took an awful lot of coincidences for JFK to be in a position where Oswald could shoot him.
I don’t believe all those actions were by coincidence.