'Starting assumptions' as I used it is basically the same concept as 'terminal moral values', and a terminal moral value that refers to humans specifically is arguably more complex than one that talks about life in general or minds in general.

More-complex terminal moral values are generally viewed with some suspicion here, because it's more likely that they'll turn out to have internal inconsistencies. It's also easier to use them to rationalize about irrational behavior.

So then what did you mean by this?

I think "making the argument that humans have some special moral place in the world" in the absence of an eternal soul is very easy for someone intelligent enough to think about how close humans and goldfish are "in the space of 'things that one can construct out of atoms.'"