We are NOT Los Estados. We are the United States of America.
To a Spanish-speaking Mexican, we are Los Estados. A foreigner will refer to this country in their own language, whatever it may be.
But when this country is one's own, whether by birth or by adoption, it is the United States of America.
Not a foreign language translation, but in English, our national language.
Singing the Anthem in English, if you only know Spanish, makes as much sense as the Latin Mass, or maybe less.