One thing about Bolshevik regimes and government and their supporters, they alway find someone to blame. Vietnam exports much to the USA compared to other improverished nearby countries because Americans can afford the products. Not so much in Cambodia or Laos. 

As Jimmy Carter pointed out when he spoke to the Cuban people onTV, the embargo has had a negative impact on Cuba, but Cuba had full trade relations with some 150 countries, including most of the EEU, Japan,China, etc. He pointed out that the same boshevik economic model that ruined the economies of the entire Soviet Bloc were in place in Cuba. The main thing the US embargo did was give Fidel a fig leaf to cover his regime and its command economy. . Remember in the early 60s....Castro decided...against all logic...to try and take over the world sugar market.  He didnt. The price of sugar fell, the Cuban economy collapsed, nothing on the store shelves by 1964. Cuba had to get the Soviet Bloc to bail them out.