Which, I think, is fair, as South and Latin are also America. And so is Canada. And so was Francis.
But I usually find it a hard concept to convey to my fellow local USsians.
I think you illustrated why the concept exists. USA actually has "America" in its name, unlike others - hence 'Americans' and not 'USsians'.
The United Provinces of the Río de la Plata (Spanish: Provincias Unidas del Río de la Plata), earlier known as the United Provinces of South America (Spanish: Provincias Unidas de Sudamérica), was a name adopted in 1816 by the Congress of Tucumán for the region of South America that declared independence in 1816, with the Sovereign Congress taking place in 1813, during the Argentine War of Independence (1810–1818) that began with the May Revolution in 1810. It originally comprised rebellious territories of the former Spanish Viceroyalty of the Río de la Plata dependencies and had Buenos Aires as its capital.
source: https://en.wikipedia.org/wiki/United_Provinces_of_the_R%C3%A...