Ending the United States of America sanctions are democratically supported in the United States. The sanctions that were imposed on Cuba was back during the Cold War, and was a long time ago. Many things have changed since then and most people in the United States would support ending the sanctions.
The economic sanctions against Cuba, sanctions that the entire international community save both the US and Israel, if the UN is to be trusted, are against, are only done due to outdated Cold War politics and to appease the Cuban community in southern Florida. They are not done because the vast majority of Americans support them or for any sensible reason whatsoever.