I also downvoted your answer. I should also point out that the question is discussing whether or not "minus one" can be used in the plural, not whether "one" can be used in the plural, as you say here.
Your examples are talking about the preposition "minus" and the noun "one" (or they appear to be — more context would help), but the question is about the noun "minus one". Not addressing this distinction at all was part of the problem I had with your answer.
Also, saying "no exceptions" when there are people who clearly accept "-1 people" and don't like "-1 person" is a bit misleading. Either you are ignoring the evidence that doesn't fit, or you are prescribing an answer based on your own internal logic, which people don't really go for on this site.
So now you have both downvotes accounted for.