By giving them your money, you are funding the operation of the plants that produce the meat. And lining the pockets of those that make the decisions to act this way. It is not meaningless.
If you don’t give them money, it hurts their bottom line and forces either change or the shutting down of the business. You can speak volumes through making more ethical decisions about where your money goes.
“they can choose not to do that. it's not as though they literally re-order every product the moment they sell a unit.”
No shit. Most stock systems just remove that item from current inventory, and when it gets too low it triggers a reorder request.
Corporations do not abide by ethics. They do not care about anything but increasing profits. So not buying certain things causes stock to sit, and in this case expire. That hurts their bottom line, and so it is more likely to trigger change in the form of them no longer stocking said item to sell. Are you really this dense?