Your ignorance, or is it bigotry, is breathtaking. You spew nonsense right and left.
Dual citizenship wasn't legislated, it grew out of the judicial branch, most recently from Supreme Court decisions in the 1950s. It's applicable to dozens of nations (I believe around 50) and it's nature is determined by the laws of the other nation, not the US. For example, if Cuba decides Cuban immigrants to the US or their descendents hold dual citizenship tomorrow, they're US citizens. Until then, they're US citizens in the US, Cuban citizens in Cuba.