The article assumes rational behavior with regard to everything except which methods of committing crimes are possible and concludes that punishing impossible a

The article assumes rational behavior with regard to everything except which methods of committing crimes are possible and concludes that punishing impossible attempts creates a rational disincentive to all attempts. It's right in a game-theory sense, but not a practical one. Proving intent to a jury is based on circumstantial evidence. Shooting a gun at someone is strong evidence of intent to murder because it is widely known that guns are lethal. Countering the weight of that evidence would require very convincing evidence that the shooter did not believe his actions would be lethal. Proving that someone believed burning a voodoo doll would be lethal would be very difficult since it is widely known that burning voodoo dolls is not lethal. Even apparent evidence that the voodoo practitioner had a genuine belief is easily played off as an act, and in criminal law, the benefit of the doubt goes to the defendant. There's also the matter of people having mistaken beliefs about the probability of punishment.