The typical demonym is inaccurate.
It is more or less “USian” in some other languages, and no one raises an eyebrow. 美国人, 米国人, etc.
It is more or less “USian” in some other languages, and no one raises an eyebrow. 美国人, 米国人, etc.
Given that both of those examples come from phonetics for America I don't think that proves what you think it does. It's not 合众国人 ...