This summary is quite useful. Eliezer, it would be very nice if you added forward links to your post. I often find myself wanting to recommend reading a series you've written to a friend, but in order to read it they would need to start at the end and link their way back to the beginning. If a link to follow ups were provided at the top or bottom of prior posts, it would make these a lot easier to follow write on a particular topic, since I could recommend one post and my friend could hopefully figure out the rest.
This is certainly an insightful post. I'm not sure the example is that compelling though.
If you argue with a young earth creationist, they could full well understand what you mean, but simply disagree and claim "God did it," is a simpler explanation still. In fact, if we were to presuppose an intelligent being of infinite power existed and created things, it seems it would actually be a simpler explanation.
Most people, though perhaps not all, who have no belief in an omnipotent designer will pretty quickly accept evolution. So that might not be the cognitive problem in that situation.
I'm sure there are examples out there (opposition to free trade, perhaps?), but the rejection of evolution in favor of creationism is rather more complex and deep rooted.
Tiiba: Because it is very hard to read ambiguity into moral acts. One can say that six days is not meant literally (even if the original language says that - though I'm not saying it does; I don't know). One cannot say that the firstborn of Egypt were all just sleeping.
Furthermore, one cannot explain away deception. Maybe God actually made the Universe in six days but wants us to think it was longer to test our faith. Yes, that's a lousy argument, but one might conceive of it being true. As for other offenses, God makes the laws of physics, so he obeys them at his whim.
By contrast, an action making God appear evil necessarily makes him incomprehensible for many religions. If you say that God is good, and that he slaughtered innocent children, and you believe that such a slaughter is wrong, then any defense of God must change the meaning of "God is good" to something completely unrecognizable. Either good is true of God by definition (What He does is good) or it is the "big plan" strategy, in which case it is actually good but you are too stupid to understand why, meaning he is good in a way that we necessarily cannot understand.
So, to end this rambling, people pick moral attacks because they don't allow the "Well, it's obviously false, therefore, it isn't meant literally!" defense. It also attacks concepts of God on a somewhat different level.