(I posted the comment below first at Unfogged but it was too good to just waste on those ingrates.)
What you need to keep in mind when judging Castro is that the man has stayed in power for almost fifty years and is only giving it up because his health has detoriated. This despite enormous odds against him, what with a certain superpower not a hundred miles away not liking him much. Unlike the Eastern European socalled socialist countries, his regime did not crumble once Soviet support was withdrawn, nor did Cuba go the Chinese or Vietnamese way of economic but not political freedom. At the same time his regime has been repressive, but it hasn’t engaged in mass murdering opponents in the same way US backed dictatorships in central America have done, or even (afaik) in the kind of repression that China went through.
That suggests to me that the reason Castro has survived so long in the face of so much difficulty is because the Cuban people want him to and believe he is their legitamite leader, despite some of the nastier features of the system he built.
What might help with this acceptance is the example of neighbouring countries like Haiti, with its history of brutal dictatorships, short periods of democracy undermined by Uncle Sam and civil wars/chaos…
Cuba is poor, but doesn’t have the extreme inequality of many Latin American countries, has free healthcare and school system for all its citizens annd has been able to go its own way despite superpower pressure. Would Cubans want to give up these hardwon achievements in return for the often dubious freedoms of liberal democracy as defined by US foreign policy?