Much of the American left continues to admire and support Castro's regime. 

Consider the case of the American Library Association and the Independent Library Project in Cuba.  If you are one of those Cubans who doesn't have the "convertible pesos," and you want to get books that the Castro regime doesn't approve of, you have to find an independent book lender. And you would have to convince the book lender that you are not a government agent, because the government's response to this movement is to arrest and imprison the independent librarians. 

Now you might think that the American Library Association, which categorically "deplores any restrictions ... that inhibit the free flow of information among librarians", to side with the Independent Library Project in Cuba.  You would be wrong.  The ALA Latin American and Caribbean Subcommittee (of the International Relations Committee), refused to recommend that the ALA condemn the Cuban government's treatment of independent librarians.  After hearing both sides, those who favor the Cuban government and those who are being thrown in the slammer, the LAC Subcommittee issued a report.  Here is a juicy passage:

Let me unpack that for you.  The Cuban government regards independent librarians as agents of outside powers, hostile to Cuban socialism.  That, of course, is how tyrannies view any attempt at freedom of thought: it is treason against the state.  The ALAsubcommittee endorses this view.  Because the independent librarians get help (see: books) from folks outside Cuba who are not fond of the Cuban regime (where else would they get them?  Not, I think, from the ALA), they are therefore not really "independent." 

Of course that doesn't mean that the ALA doesn't take sides.  It is firmly on the side of the regime. 

Of course the "library colleagues in Cuba" aren't "independent" either.  They are creatures of the regime.  The ALA has made it clear whose side it is on.