1959 was a long time ago.
Should we (the EU?) have sent weapons to the Venezuelan opposition in 1999? When exactly did Chávez become a dictator? He was clearly not a democrat (coup attempt in 1992) but I think it would have been premature and unlikely to have had good outcomes if we had done it in 1999 or 2000 (he was democratically elected both times). He was obviously a dictator when he died in 2013 but a large part of the Venezuelan population still hadn't cottoned on to it or they thought it was great.
Iran was similar. The crazies were quite popular in 1979.