But I made the case that eating meat isn’t immoral. The act of purchasing meat was the immoral act.
If I understand the argument here, you are observing that slaughterhouses will continue to operate as long as people buy meat. What consumers do with the meat they buy---eat it, throw it directly in the trash, wear it on their heads---is morally irrelevant because it has no impact on whether animals will continue to be killed in the future. If I have that right, when you assert that the purchase matters more that the eating, you seem to be advocating for consequentialism. Ethicist Peter Singer, famous for his formulation of animal rights, happens to take a consequentialist position, and more specifically, a utilitarian one.
Here are two opposing perspectives to consider.
1) Wasting edible meat is immoral: One may argue that if you eat that meat, then you are preventing animals from "dying unnecessarily". You need to eat, and if meat is going to be part of your diet, then purchasing meat is ethical. So there is a debate to be had here over what is and is not necessary. But if meat is good food, then wasting meat that you have purchased may be a problem. One variation on this would be John Locke's argument that picking a bunch of apples and letting them rot in your barn is immoral, because you are depriving other people from eating them.
2) Eating meat is immoral regardless of how it is obtained: You do not elaborate very much on why eating meat is immoral, but the specifics of this argument matter. In the Jainist religion, for example, eating meat itself would be seen as a violent and unethical act in violation of basic principles. It would be worse, from such a perspective, to eat the meat oneself than to dispose of it in some appropriate way.