Not precisely---most of the arguments I've personally seen on the topic (here included) boil down to "it's not fair they do that," with no clarification as to w

Not precisely---most of the arguments I've personally seen on the topic (here included) boil down to "it's not fair they do that," with no clarification as to what framework of fairness the plaintiff is using. Because there are multiple non-overlapping frameworks of fairness in play. The money in question here, for example, is paid by foreign citizens in non-US countries. How much of that money is owed to the US government, and why? How much owed to the nations from which those citizens hail, and why?