The Nash equilibrium is also natural, efficient, and non-optimal in many cases. Which, in the face of "optimal", could be described as "wrong" if the belief is that optimal is desirable.
Just because something is "natural" doesn't mean it can't be ethically wrong. We have another word for things like that--they're called "amoral" and it literally means there is no ethical choice being made. The concept of "natural" is orthogonal to this.
Lots of things we consider "natural", we also pride ourselves on the ability to choose not to give in to.
Vice versa, there could be things that are "not natural" which--oh wait, no there aren't. To be "natural" is one of those really stretchy concepts that can include anything if you argue it the right way back.
For instance, this discussion is about a copyright bill. Is that natural? Is copyright natural? Is economics? Politics? Rationality?
We also have a word for such terms in an debate: inconsequential.
Not to speak of the idea that anything that is "efficient" must be amoral. In my opinion exactly the opposite is true. Most things which are "efficient" read pretty damn strong on my right/wrong moral compass--either I think they're pretty cool, or I think they're pretty terrible. There's really very few efficient things that make me feel "yeaaaahhh, it's efficient sure, but meh. you do you".
Things that are efficient you need to consider extra carefully exactly because the efficiency can swing the needle on the moral compass rather dramatically!
Killing newborn cubs and impregnating the mother with your own is also very natural and efficient. I hope you agree it's also very wrong and that the argument from nature is an amazingly awful argument.