The US embargo -- and the palpable external target it presents -- is a major source of the longevity of the Castro regime (and the longevity of the regime itself motivates the maintenance of the embargo), so in a very real sense all of the misery resulting from the regime also can be blamed on the embargo, and vice versa. They aren't independent factors.
I don't disagree. The Castros have been helped plenty by the embargo by keeping public distain focused on the US rather than their own government's policies.