If you have citizenship from two different country's, you have what the framers wanted to prevent (post grandfather clause) with the inclusion of the NBC requirement for the Commander in Chief...divided loyalties.
If one is born in country, to two citizen parents and never obtains (or is "granted") citizenship by another sovereign...that person will have no loyalties "owed" to another country.
It should be clear to most why the United States would/should NEVER want a Commander in Chief of the armed forces to have multiple allegiances...loyalties owed to another country.
Dual citizenship/dual alligiences wasn't a good idea for the CinC in 1787...nor is it a good idea in todays world.
Barry O. very clearly has allegiance to two countries, Kenya and the U.S.
He violated the Logan Act and campaigned for his cousin in Kenya while he was a sitting U.S. Senator.
That alone demonstrates his divided loyalty.