That seems true in the general case, but not in the specific. One can still obtain SSI if you never worked a day in your life, assuming you can shelter your inc

That seems true in the general case, but not in the specific. One can still obtain SSI if you never worked a day in your life, assuming you can shelter your income to pass the means test, and then return to live in the US. It's not a very likely scenario, because if you have the wherewithal to live abroad and shelter income, the paltry SSI isn't worth the effort. Still, it begs the question if citizens have some obligation to pay some minimum level of taxes, albeit small, for the basic services and protections one would still expect as a citizen: the right to vote, the salaries of your representatives, courts and foreign service, etc.