The Stumped blog at the Washington Post explains it all for you.
Why do we have an embargo against communist Cuba, while we outsource our manufacturing base to communist China?
Here’s the short answer: No sound reasoning explains Washington’s schizophrenia in dealing with Havana and Beijing.
When it comes to China, the foreign policy of the United States is predicated on a belief that the more you engage a totalitarian communist nation — through trade, regional diplomacy, investment, tourism, educational exchanges and simply by smothering it with American culture — the more likely it is that democracy and individual rights will take hold in that nation. The theory is that the regime’s tight-fisted control of everyday life will be eroded by outside influences.
When it comes to Cuba, however, the foreign policy of the United States is predicated on a belief that the more you isolate a totalitarian communist nation — cutting it off diplomatically, imposing a trade embargo and preventing people from traveling back and forth — the more likely it is that democracy and individual rights will develop in that nation. The theory is that the regime’s tight-fisted control of everyday life will decay because of the lack of outside influences.
“Stumped” pretty much gets it, noting that the combination of the clout of the Cuban exile community, the cult of personality over Fidel both here and there, and the fact that the one thing that is propping up the Cuban government is the embargo itself are all factors in drawing the distinction between China and Cuba. But for all that, there’s still the elusive element that was once explained to me patiently by a colleague who was born in Havana and moved here when he was ten: “It’s a Cuban thing. You wouldn’t understand.”