Both Hillary and Bernie Sanders support the ending of the U.S. embargo against Cuba. If you believe that trade with third world countries leads to oppression, why would Bernie support the ending of a trade embargo with Cuba? Instead, it seems like Bernie is saying that trade with Cuba promotes both national security and that it benefits the people of Cuba.

https://berniesanders.com/press-release/sanders-statement-president-obamas-historic-visit-cuba/

“I applaud President Obama for making history by traveling to Cuba and moving relations between our two countries into a new era. This is an approach that is long overdue. I continue to stand by his calls for Congress to fully lift the failed embargo. Fifty years of Cold War is enough. It is time for Cuba and the United States to turn the page and normalize relations.”