You are really hung up on misinterpreting this. I'm not sure if it's intentional or not, but this is like the 4th place you've confused "must accept cash for payments" with "must accept a cash replacement for goods or services purchased". Clearly, if I buy a good from you, you have to deliver me that good. And I have to pay you in some form. Because I am giving you a credit card or other cash equivalent, you have to accept cash (up to a certain level).