That’s not the point. Walmart has plenty of buying power to dictate what payment methods they once supported in their POS systems are still supported.
You take your car to the shop. They tell you that your water pump needs to be replaced. You decide not to replace it and keep adding fluid to your radiator. When your car breaks down, do you blame the auto manufacturer for a faulty water pump? How about the repair shop for not insisting that you need to replace the water pump?
If a POS vendor tells a retailer they have to cut support until a vulnerability, do you think the retailer insists on continuing to use that payment source? I guarantee theyre going to insulate themselves from liability, to hell what the public thinks.
Im just saying that there are likely technical reasons for the change. Its not done to spite you. Its done to protect them.