How?
The ubiquity of intelligent design is such that, like the air you breathe, it goes unnoticed. It is considered natural only because you were born into it and have become accustomed to it.
As it happens, I notice the air I breathe because I'm allergic to much of what it carries. In any case, your statement is, in fact, nothing more than, "stuff exists."
At any rate, Intelligent Design is well-qualified to be called a "theory," because it explains the data, which, if it were without design, would be incomprehensible to reason and senses.
Here we go again. Intelligent design explains nothing, it predicts nothing, and it has nothing to do with science. Your Grand Theory that states "Nothing is comprehensible except for design" is so vague as to be meaningless. I was in the Navy. I can comprehend the ocean. Where's the evidence that it was designed? That it always and everywhere mysteriously goes exactly to the shore and no farther!!?
You again conflate human intelligence, for which we have evidence, with some sort of "other" intelligence, for which there is no evidence and which is beyond our ability to test.
Can you state something that ID doesn't explain?
I'm coming to believe there may be something to The Hitchhiker's Guide theory, which is that human thought is considered to be so primitive that it's considered to be infectious disease in much of the universe
By ascribing detail to the "stuff," namely organization and predictbility.
As it happens, I notice the air I breathe because I'm allergic to much of what it carries.
Is it all you think about? How about gravity. You may say it is "natural," but why? Is it because it is really natural, or only because you've lived with it all your life? The distinction between natural and supernatural is arbitrary, moreso than the distinction between species. It is not a scientifc distinction, but a semantic one that depends upon each observer.
Intelligent design explains nothing, it predicts nothing, and it has nothing to do with science.
As I said, intelligent design predicts organized matter that behaves according to predicatable laws will be found. That is far more than nothing. It fairly well fits everything. Take a single drop of water out of the ocean and descibe all of its attributes. The fact you can see it in the first place is but one small sign that it is designed. It's organization and predictability can be described in great detail.
Can you state something that ID doesn't explain?
Not yet. Can you enumerate something science can do with out making use of either intelligence or design or some combination of the two?