Americans or Cuban-Americans?

Some articles about President Obama's relaxed restriction on travel to Cuba say "Cuban-Americans", others say "Americans", others refer to both in the same article. Which is it?

And if it's Cuban-Americans only, I have another question: since when can the government discriminate between the rights of certain Americans versus other Americans? An American citizen is an American citizen, and it's illegal to discriminate between groups, whether along ethnic lines, race, color, religion, or any other parameter.

Why is this not mentioned in the news?