Argentina issued the bonds on explicit terms that it will pay everyone equally - even if they agree or refuse some future deal. Argentina dislikes them from not agreeing to it, but that's it - only a dislike that doesn't give any rights to pay them differently than others; they didn't have to agree to the haircut, so it's within their rights to demand to be paid whenever the others get paid.
For your CC example - yes, it would likely be different in personal bankruptcy, but that's not relevant because personal bankruptcy intentionally gives much more protection than sovereign bonds, the rules are quite different there. And sovereign defaults don't wipe you as clean like a personal bankruptcy does in many western countries - and there are jurisdictions where you don't get personal bankruptcy, and you keep the debts until you die. And in some places, even after that - the debt transfers to the heirs.
