This wasn't actually about Aristotle's definition of a human. It was about deducing items already given in the definitions of Aristotlian labels.

I believe Aristotle's actual definition of a human was [rational, animal]. The point Eliezer is making is that, given this definition, it's an empty argument to say "Socrates is human, all humans are animals, therefore Socrates is an animal." This is blindingly obvious and completely unhelpful when you replace "human" with [rational, animal].

In other words, it sounds like a major insight, but that Socrates must be an animal if he is human is in the very definition of human. It did not give you any new insight in any way if you already knew Aristotle's definition of animal.

There are other things you can deduce logically from these definitions, but it's dumb to deduce something that is already given in the definition. That's the point.