Free Med School in Cuba for US Students

I just read this article about 8 students who graduated from medical school in Cuba. They have no debt, because the program was fully funded by the government.

Uh, not everyone in Cuba can eat, but they can afford to educate citizens from another wealthier country for free? I don't understand. And it's not as if these students are planning on staying in Cuba to practice medicine, though they are committed to practicing in poorer neighborhoods.

Don't get me wrong, I like the idea of debt free med school for that reason, but it seems odd that Cuba is the one doing it.

Am I missing something?