I don't see what's so idealistic about it. Mexico, Chile, Argentina, and Brazil are all now substantially wealthier than Cuba. That wasn't the case 50 years ago, and it's not crazy to think it would have been wealthier absent Castro.
And FWIW, I oppose the embargo, and think as far as dictatorships go, Castro's is pretty mild. I also acknowledged that his regime has real, substantial achievements in social welfare - health in particular, and that without him, Cuba would probably have more severe poverty.
Pure riches don't mean jack - what use is to make riches , if it remains in the hands of an elite, not distribued, answer the left. As you implies.
Batista's regime made Cuba a large brothel and casino, blunt truth. Castro may have been better, finally.