Your argument is only true in the trivial sense that sexually reproducing organisms are only viable in larger numbers than a single pair; but that's a distinction that doesn't demarcate anything interesting. Humans are like ants, you say, but your argument also leads to the same conclusion about tigers, bears and other solitary animals in that they need more than a breeding pair to be viable. It descends into tautology.

Yes, humans are somewhat like ants in that they are usually social. Humans are adaptable enough to survive in pairs, though lack of specialization means they won't necessarily live the most comfortable life, so it would be an unusual choice. But there's nothing elective about ants' socialism. So in the end I don't think your argument works.