[SamAdams76]

That would be Indian. But evidently the maker of the map was trying to be “politically correct.”

[TigersEye]

Then why are Aleut/Eskimo and American Indian listed in separate categories?

[Lurking Libertarian]

That would be Indian. But evidently the maker of the map was trying to be “politically correct.”

You didn't read the article:

"Almost 20 million people claim to have 'American' ancestry for political reasons and because they are unsure of their family's genealogy."

[Albion Wilde]

The third item down on the list states American. I don’t get it.

That would be Indian. But evidently the maker of the map was trying to be “politically correct.”

Incorrect assumption. The article at the link states in the subheadlines under the title: "Almost 20 million people claim to have 'American' ancestry for political reasons [or] because they are unsure of their family's genealogy".