So if your going to explain an event in the past, you have to invoke a cause which is known to produce the effect in question.
That rule would be rather unfair to creationism, wouldn't it? Supernatural beings aren't known to cause any effects, are they? They aren't even known to exist.
"Code" is known to be a prerequisite for all observed intelligent designers, and therefore, at least partially, a proximate cause of the "effect" known as intelligence.
It's always worth remembering that when humans intelligently design things successfully, those things must fit and function in the physical world. This constraint also applies to nature's unintelligent designs. That's probably the main reason why there are often resemblances between the two.
Because we make fire, it does not follow that volcano gods are responsible for volcanic activity or that lightning gods are necessary. Because we make canals, it does not follow that all waterways that can function as transport routes were intelligently designed.