The claim here is that if we let animals go they will die in the wild
By continuing to consume animal products one is causing animals to be bred into existence. To say that the animal would die if released is missing the point, because by ordering a cheeseburger one is increasing demand for the breeding in the first place.
The claim is that, because of carnism, we have all these animals. Therefore, we must continue carnism to continue breeding these animals. This is circular reasoning and doesn't justify one's own personal choices. Nor does it justify carnism in the first place.