A majority of Americans speak English as their native or sole language. Great. But the second most common language is Spanish. Also great. Neither language is inherently superior to the other linguistically. Neither language is inherently superior culturally.
English and Spanish aren't even all that different in grammar, sentence structure, and some vocabulary. Same alphabet, just a few accent marks to learn.
All true - but not the issue.
The recognition that English isn't the sole or privileged language in the US acknowledges that the US is a diverse country made of of a whole slew of backgrounds. One of the ways to recognize this is to give anybody the option to express themselves language-wise in at least the two most common languages spoken in the USA.
But why stop at two languages?
I don't know what the third-most-common language is in the USA. Let's assume it's Italian, which is even closer to Spanish. Why not have tests available in Italian? Or in the fourth-most-common language, whatever it is (Japanese)?
It's not about intelligence or some imagined form of superiority; it's about standardization and cost control. An amateur radio license isn't a right; it's a privilege, too. People have the right of equal access (meaning everybody has the same requirements) not the right of equal result (meaning everybody gets a license).
It's not too much to ask that anyone who wants a US amateur radio license have at least some understanding of how to read and write English. Accomodations for the disabled (such as Braille or having the exam done orally) are OK because a blind person cannot learn to see, but a person who doesn't speak English can learn the language at least well enough to pass the tests.
IOW, basic English literacy should be a requirement.
73 de Jim, N2EY