Merchants are “double dipping” when charging checkout fees

One thing to consider in this debate: The price of credit is already being paid by everyone. The merchant’s overhead cost of processing credit is already part of the price of everything you buy, whether you use credit or not. The cost is built into the prices they set. So unless they first lower all their prices across the board for everyone, and only then charge a checkout fee to a customer paying with a credit card, this plan to add a checkout fee seems to be “double dipping.” Credit customers would be paying twice for the cost of credit.