That Eliezer would be upset if someone got it right before he did seems obviously absurd.

As explicit reasoning, yes, that would be absurd. But we are all primates, and the thought of being overshadowed feels bad on a subconscious level, even if that feeling disagrees with conscious beliefs. "I will do it right and anyone else who tries will do it wrong" is an unlikely thing to believe, but a likely thing to alieve.