Also, it is already dead, so why not go ahead and eat it". Of course, this is what they tell you as they order the "lamb shanks" in the restaurant.
This is different than the point I was bringing up. The "its already dead" excuse can also (still erroneously) be applied to the meat being sold, by someone buying it. The issue isn't that the animal has already been killed, it is whether or not one is creating the demand for that "product". The store already does the damage by having to re-order more death when they threw out the cadavers. As dumpster diving does not create demand for animal products, that consumption does not become demand down through the supply chain back to the breeders. The "already dead" excuse that people may use before buying flesh does cause a ripple of demand back to the breeders and more animals are brought in to existence to be slaughtered as a result as that will yield more money for them. Also on a similar note: If someone broke in to a store and stole the meat, it would also be supporting animal agriculture as the store would then have to order even more to make up for the stolen "product".
It may seem like splitting hairs, but the demand generating aspect is where the real driver of the crime is. Having said that, I do not promote meat eating under any circumstance, unless you are somehow stuck on a deserted island and have to eat the magic chickens that feed off of sunlight and asinine arguments.
So I guess to me, anyone who abstains from supporting the animal agri-business is a vegan, even if they ate meat from a dumpster or roadkill. It's not about what you eat, it is about who is hurt by your decisions (and payments). As I said before, this doesn't apply in my case as I would never eat such stuff anyways...
edit: The above paragraph could be misconstrued to seem like I would support hunting. I do not, of course. The line "It's not about what you eat, it is about who is hurt by your decisions" would hopefully cover that, but I do want to make it clear that I of course do not support the "sport" of hunting in any way.