Earlier quoted context omitted.
You are wrong about US legal tender. You have to know about the history of currency in the United States to fully grasp why those words are there. The simple explanation is the Coinage Act of 1965, Section 31 U.S.C. 5103[1], entitled "Legal tender," states: "United States coins and currency (including Federal reserve notes and circulating notes of Federal reserve banks and national banks) are legal tender for all deb…
But on the bill itself that Im holding now it says “This note is legal tender for all debts, public and private.” Once you owe someone money they can state their preference for card/check, but they cant flat out refuse cash.
The words don't imply that paper currency must be accepted for a debt, simply that the currency can be used for a debt.