His family left Cuba. The Florida Senator was introducing Romney in Florida on Saturday.
UPDATE: On Mitt Romney's campaign plane shortly after the rally, Rubio was asked what he meant by the comments.
"I'm talking about big government. I'm talking about countries where the government dominates the economy," Rubio, whose parents left Cuba, replied, noting that "virtually every country in Latin America" was governed by the policies he was condemning.
"The president's just not a supporter of the free enterprise system," he said, adding, "This isn't the first time I've said it, and I believe it with all my heart."