This is a question about the English language from someone learning the language, not a math question.

The answer is obviously because programmers want to be able to write

  f”{n} result{‘s’ if n == 1 else ‘’}”

I rather like Greek for having a dual form as well as a singular and plural form. (Translators made me add dual-form messages as well as singular and plural form messages).

> This looks like proof by assertion

It’s not a proof at all, by anything. It’s a description of the singular / plural distinction in English.

> Linguistic tautology is not mathematics. That way lies madness.

Singular vs. plural is not a mathematical fact, it’s a linguistic fact. I’m sorry you consider that bollocks.

> The second example I give of "zero threes" does not imply that three is plural. If anything it merely implies belonging or associativity in a linguistic sense and certainly not a maths sense.

It absolutely does denote plurality. "0 threes" uses "three" in the plural form and "1 three" uses "three" in a singular form.

Thus is not a question about math, but about linguistics.

I find your tone excessive here and expect better from hn. It's just a question and a semi-interesting one at that.