I tend to the view that most works of fiction have either inconsistancies or "holes" in the narrative.
It is these which makes it p[ossible for writers to write additions to their original works.. some for the better.. some for the worse.
Sometimes looking into these can proviode a greater insight into the stories themselves.. (vis my heretical views, not just on CON but other works too)
Also.. they can promote dialog between those interested in the works, which can also lead to greater insights.
As to this particular inconsistancy I think it can be resolved by.. "How is Humanity defined in this context". I tend to the view that "humanity" is taken to be NOT the physical shape etc.. but more the capability of being able to reason.. to make a decision based on the events one encounters currently and before thedecision. In effect the ability to be culpable for onesactions.
I think that the talking animals in Narnia would certainly fit this criterea, and so would remove the apparent inconsistancy.
(and just to emphasise an earlier point.. this explanation of mine is NOT intended to represent what WAS intended.. but will probably induce further discussion, both for and against.)
/me retreats back to his Dark Dark corner to await the Stoning