I'm not going to add anything that hasn't been said. I am not normally a fan of alternate history stories - they usually require some obscure knowledge of actual history. In this case, not so much (who doesn't know that Fidel Castro has been the leader of Cuba for the last 50+ years?).
In this case, it is not obvious that Cuba would not become communist just because Castro was not the leader. OK, that sentence has too many negatives - without Castro, is it really clear that Cuba would not have become communist? Was he absolutely essential to that process? The story even notes that there is a revolution. Couldn't the current leader of that revolution have brought the country to communism just as easily? And perhaps with an even worse outcome? Granted, a short story can't necessarily answer all these questions. But in my mind, there was still too much up in the air.
Loved the reading, Bdoomed!!