But more people pay American taxes than just citizens. I've got many friends here on work visas and they all pay American taxes, too. The two terms have huge ov

But more people pay American taxes than just citizens. I've got many friends here on work visas and they all pay American taxes, too. The two terms have huge overlap, but are distinct - neither is a subset of the other. Nor is either strictly correct in this case, as the USPS is a self-funded quasi-governmental agency. It's other customers that are subsidizing this loss.