“ALL are Americans, if you apply the same practice of naming people based on the large classification of their continent; i.e., Europeans, Africans, Asians, etc.”
“Americans” for all it matters, refers solely to the citizens
of the United States. Canada is the hat of the North American
continent and Mexico the socks. Mexicans are not Americans
and the same for Canadians. In your context, “North American”
would be true. Who wants to be called that?
What about South America? You know, that little land mass mostly below the Equator?