The embargo has proved that unilateral sanctions do not work. The embargo imposed on Cuba has not given anybody freedom.
It is disingenuous to claim that the sanctions against Cuba are about liberty. There are many states in the world which the US does not punish for their human rights record. The true reasons for the embargo are political, the Cuban-American lobby decides elections in Florida, a swing state.
The claim that US is weak to give in to Cuba is based on stubborn machismo rather than pragmatic politics. It is pointless for the US to remain unmoved on the embargo just to prove a point when the sanctions have been largely ineffective.
The sanctions against Cuba are not truly about freedom. Insisting on measures that do not work is pointless posturing.