Because it’s pedantry. Check every dictionary for america or american. Or just type “america” on whatever search engine. First thing is always the US or its citizens. If anyone ever means to refer to the continent they usually say north/south America or “the Americas”.

Go to any country other than the US and ask a local “Are you american?”. They’re all gonna say the same thing. “No, I’m Mexican/Canadian/Chilean/etc.”

Whenever a word has multiple meanings, you’re supposed to use context to figure out which one is being used. Well, the article title mentions the US government. It’s also a very common phrase with a well established meaning. Check out Green day’s american idiot, for example.

Really doesn’t take a genius to understand what op meant.