Originally, these sanctions were because Communism was the greatest threat to democracy. Yet our fourth largest trading partner is none other than China with no sign of leaving behind communism.
The Cold War long over, Cuba poses little threat to the US, making the sanctions unnecessary. The collapsed USSR being the largest reasoning behind the sanctions of Cuba makes the continuing sanctions nothing less than petulance.
Those reasons behind the sanctions never did actually materialize and, as a result, the sanctions serve no purpose today. In this case, we are the oppressors and not the actual government, which we have embargoed.
We have no business governing other countries, unless they actively threaten us, are systematically oppressing their people, or are clearly a cruel regime.