THE PEOPLE FROM USA...HOW THEY DO NOT HAVE A GENTILIC

Gentilic is defined as name of an inhabitant or inhabitants of a country, region or city.
In my case "Colombian" because I was born in Colombia, "Australian" then to someone born in Australia.
What is the gentilic for United States of America?
American?
Nooooooo!!!!!!!!!!
American citizens are so selfish in their language they call themselves "Americans" when America is a continent and not just one country.
In that case Americans are also from Canadians to Argentinians, even myself, I was born in a continent called America.
So how to call the people from USA?
At least in english there is not other way, leaving them as probably one of the countries in the world without a gentilic.
Even english (people from England) have a gentilic, so it is not a matter of english language.
In spanish we can call "estadounidenses" to the people of USA, however that is a second mistake, because there are also other countries named as United States, for example (Estados Unidos do Brasil or Estados Unidos Mexicanos).
This all lead me to only way the people from USA can be named, and that is a before-pejorative (derogatory) GRINGO, which is not a gentilic for white people but for the people of USA only.
By the way, gringo is actually coming from two words in english GREEN-GO, which became famous during Vietnam War, shouted by Vietnamese people regading USA soldiers.