This is arguing fast and loose with Aquinas. Aquinas would argue that it is permissible to steal bread to feed a family because human beings have an inherent right under natural law to the food appropriately required to stay alive. A right exists for a starving man to eat bread to stay alive and a rich man does not have a right to hoard bread he does not need if hoarding that bread directly causes someone else to starve.
Human beings are not food for other human beings. Ergo we have no natural right to treat other human beings as if they are food OR to kill them in order to use them for food.
The other issue is how is it decided when the circumstances are dire enough to warrant killing and eating another human being? Would a mother facing the starvation of her five children be justified in killing one to feed the others? I don’t think so.
I would suggest the proper human answer is to hold to the position that we are all in this together. We all live or we all die. There is something much more proper, decent, moral and human in NOT succumbing to the temptation to regard one another as mere food (or, as you claim, merely animals.) We aren’t.
I suspect God would be more pleased with us if we were willing to die rather than turn one of our number into our next meal. There is something much more honorable in being willing to die by starvation rather than compromise the right of another to life.
I also suspect that God realizes – as we should – that our life on earth is merely a transition to eternal life. Why would we succumb to the temptation that our earthly existence must be preserved at all costs – even to taking the unprecedented step of murdering someone we love merely to preserve our own skin?
I am not sure where you are going with this, but I highly doubt that God’s request of Abraham would lead to making spare ribs of Isaac.
I also doubt that you understand the deeper meaning of this event and request. It wasn’t a proof test to demonstrate Abraham’s loyalty and faithfulness – it was an acknowledgement by Abraham of his guilt for being disobedient and distrustful of God. He knew he deserved to lose Isaac and was forfeiting back to God the greatest blessing that God had given him to that point since Isaac represented everything promised to Abraham by God – making him the father of a great nation through Isaac.
There is much more to this and your using the story to bolster your argument fails.
No, man is not merely “an animal.” Neither have you shown that killing and eating another human being is “a rational act.”
Just because some human beings abdicate their rationality, humanity and moral agency does not entail that humans are, therefore, animals. It is possible for human beings to make themselves less than they essentially are, but it would be impossible for a lesser being to bootstrap itself into a higher order of being, although the Mormon religion essentially teaches this.
I suggest you read a bit on the differences between vegetative, sentient and rational beings in the following article, appropriately called, “Stop It! You’re Killing Me.”
edwardfeser.blogspot.ca/2014/03/stop-it-youre-killing-me.html