We do have a reputation

Cuba government has mobilized citizen defense militias, saying it fears a U.S. attack during Fidel Castro's health crisis, even though the White House insists no such threat exists.
[...]
After all, we have military bases in Cuba, though this never comes up in conversation with bug eyed, Castro hating, virulent anti communist republikkkans, unless I bring it up. Still the naval base at Guantanmo Bay is busy, in use as a torture and detention camp for any middle eastern males - including children - who happen to get caught in big net of US justice, guys like Moazzam Begg.

Then there's those recent invasions and overthrows designed and implemented by Bush in order to bring "democracy" and fight "terror" and drive up the price of oil. Afghanistan Iraq Haiti
Not to mention the failed Coup d'etat against Hugo Chavez and the reports of special forces operating in Bolivia, Amerikkkan spooks there to bring down Evo Morales. Then we have our history to consider, though I don't have all day to work on this list so it will be imperfect- Iran, Guatemala, Viet Nam, Chile, Honduras, Granada, Panama, Philippines, Puerto Rico, Nicaragua - a short, incomplete list, but I believe the Cubans when they say they fear some kind of attack from the US.
They'd be crazy if they didn't.