You've never worked in retail, have you?
When an employee has to clean up after a customer's tantrum over Apple Pay, that's one less employee at the checkout counter, or one less employee to stock shelves. That leads to customer complaints. These complaints make their way up the chain of command, but since **** rolls downhill, it becomes the employee's fault. They weren't around to check out customers waiting in line. They weren't around to restock the Magnum condoms for the horny 16 year old who buys them hoping he'll be able to fill them out. It looks bad on their performance review, it possibly puts their job at risk. All because of some self-entitled prick's hissy fit over bloody ApplePay.