What I find problematic with that mode of argument is that it tends to turn McCarthyite very quickly. Castro attempted to cut a deal with the US before going to the Soviets, he is rather less committed to communism than either his supporters or his opponents believe. He also gave the CIA the location of Che Guavera when he decided he was a liability. So there has been a basis for cooperation for a long time.
The list of crimes committed by US Presidents panicking about communism is very long. Snuffing out a democracy in Iran to replace it with a bloodthirsty dictator, supporting the Khumer Rouge after Vietnam ejected them, installing Pinochet, a mass murderer in Chile. George W Bush just managed to cause the deaths of a half million Iraqis and wonders why he isn't being praised for his efforts.
The problem isn't capitalism of communism, the problem is authoritarianism and elites who believe that brute force is the solution to every problem. Castro is a thug and a murderer but its the US who set up a torture chamber in Cuba.
Since the US government has been spending a large amount of money to get the Internet into Cuba, giving them a pipe and letting them rip with it seems like the best way forward. They will try to control it but everyone knows that Cuba is going to liberalize in the near future.
The logical way forward would be for the US to lift the blockade and let the commerce flood in. The communist system would collapse pretty quickly when there was money to be made. But the problem is that there is a faction that is less interested in bringing democracy to cuba as returning their assets that were nationalized. Since they stole the assets under the corrupt Batista regime, there aren't going to be many interested in that happening.