the same discussion applies to venezuela
If Cuba could trade freely with the US, their economy would be better. If Cuba were under a more free government, their economy would be better: also, they wouldn't be under a US embargo, and their economy would be even better.
Whether an ideological stance is worth the economic collateral damage is a value judgement.
But you can't say the embargo is not causal of Cuban poverty.
Well, the political ideology of the dictatorship and its unwillingness to be a puppet state of the USA are the cause of that embargo. As diplomacy in the Arabian peninsula shows, the USA has no issue with dictatorships and hereditary absolute monarchies provided they buy American weapons and fight on the appropriate side of proxy wars.