I’d be more inclined to argue that the child was BORN a citizen of Mexico. Period. Therefore, he was a “naturally born” Mexican citizen.
Sure, he'd be born a citizen of Mexico, due to the citizenship of his parents, but he wouldn't meet the highest standard of natural birth possible, which would also include his being born on the soil of his home country.
As per your earlier contention, no force of law would be required to make this child a citizen, but he fails the test of absolute, 100% un-alloyed ties to his home country, having been born abroad.
Let’s agree to disagree on this point, though I certainly don’t say you’re wrong.
If we could see what we DO agree on acted on in this country, say through eligibility laws or some other mechanism, HIGH FIVE, dude!