Yes John McCain is a natural born Citizen, so are Cruz, Rubio, and Obama (if he was born in HI).
Well, if Cruz is a natural born citizen then even if Obama was born in Kenya he would be eligible to be POTUS because his mother was born in the US.
So let’s follow your logic and let’s assume for a second Zippo’s father was the king of Kenya and Zippo was his only child.
What would stop Zippo from being president of the US and king of Kenya at the same time?
Netanyahu for president!
According to this article all that is required to be a Natural Born Citizen is to have a citizen (USA) mother. It does not matter where you are born or how long to stay in the country your were born in. Since there is no doubt Obamas’ mother was a US citizen, according to this author Obama is a Natural Born Citizen too, even if he was not born on US soil.