The claims are variously stated:
Carnists will go on to then claim that humans have some sort of supremacy as to why one cannot, for instance, eat an infant even though they may have intelligence at that stage less than an animal. But which is it then? Is it that we should look out for animals and mirror their behavior because we are of their ilk, or are we superior such that we should not mirror their rights? This argument seems to want it both ways.
If it were, then we would say that we have no moral obligation toward the mentally disabled or small children. Clearly, we do. This isn't about the animal's moral obligations toward us; it's about our moral obligation toward the animals. Obviously, we can't hold a shark "accountable" for biting a human, but we should definitely hold a human accountable for killing sharks needlessly by the thousands.
A toddler will walk up to other kids and randomly take things from their hands because they don't understand social norms. But any time a toddler is holding something, is it fair game for me to take? Or is someone allowed to assault the mentally handicapped or people with dementia because they might be hit by them in a fit of confusion? No, of course not. So, given that we never use someone else's morality for our own, why do we justify it in this one particular instance?
Most animals we eat are typically prey animals and not predators. All the classic farm animals are herbivores, as well as deer, quail, and almost all other commonly hunted animals. The fact that an obligate-carnivore predator kills prey "without regard" (whatever that means - did we survey lions or something?) doesn't really apply to you also killing the prey. If anything, shouldn't it be the opposite - do you regularly envision yourself, upon seeing someone assaulting a victim needlessly, jumping in to help the assailant? So this argument doesn't actually apply to the correct set of animals.
If you are reading this, you are not an obligate carnivore. The actions of an animal that does something out of necessity (or an omnivorous animal who doesn't know where its next meal is coming from) doesn't apply to humans doing something unnecessary with their grocery pickup where neat packages of ground beef are placed in the trunk of a car at the click of a button.
One could equally claim "When I look out at society, I see people killing people all the time. War, murder, self-defense. Therefore, it should be legal for me to kill another person so long as there is some prevalence of people killing people."
...and eating meat hurts other people, for instance, in countries where food is scarce due to it being exported to feed "food" animals, or in the form of climate change.