You don’t need to look further; here you have the answer from the “horse” mouth:

“It is necessary to impose financial, economic and material restrictions to dictatorships, so that they will not take roots for long years….Diplomatic and morals measures do not work against dictatorships, because these make fun of the Governments and the population”. Fidel Castro (Excerpt from the book “Fidel Castro and Human Rights”, Editora Política, Havana, Cuba, 1988)
What will bring "Change" to Cuba are free elections, the freeing of all political prisoners, and the implementation of a market economy. Everything else is “mental masturbation!”

This is one of the few times that I agree with Castro. In this case a 100%. Keep the embargo until he cry uncle.