How many nations are 500 years old?* People and cultures certainly have that long of a history, but nations? Most of Europe has been divided and redivided, conquered and reconquered so many times that most of those cultures are bastards and cross-mingled. Same goes for the rest of the world, too. It's just a fact of human history.
*The short list I can think of: Portugal, UK, Japan. Japan stays there only because of the unified change from an Empire to the current democratic-republic government without a need of a government overthrow. Even the UK isn't without its rebellions and government overthrows in the last 500 years.
Anyway, I don't blame him for not wanting to give up US citizenship, especially with what his career is. Who'd want to go do things like diplomacy when diplomacy is for the weak and poor?