It's not the keyboards. It's the keyboard layouts that are configured in software. And not all "American" keyboard layouts make that key an Alt modifier. The Microsoft Windows "United States International" keyboard layout makes it level 3 shift, for example.
And if one includes North America and South America in "American" the same goes for the Canadian Multilingual and the Brazilian Portuguese layouts. (-:
And if one includes North America and South America in "American" the same goes for the Canadian Multilingual and the Brazilian Portuguese layouts. (-: