I for one will say that there are some things that will never be understood because of the restrictions we all have on exploring the entire universe and the restrictions that are inherent in our own intelect. This is especially true if their is a supreme being. It is rather arrogant to think that we will ever know everything, or what God knows isn't it? We are forever limited in knowing certain things.
As far as throwing up our hands and saying that "God did it...", that is not necessarily the case if one believes that intelligent intervention is supported by facts and logic. It is rather simply facing up to reality instead of pretending that our own intellect is the supreme measure of all things.
In short (since you did not answer my question) the problem is that atheists cannot ever accept Intelegent Design whether it is reality or not. You have limited yourself in the search for reality by the framework that you have put yourself into. Perhaps it would be better if your were open to all possibilities of our existence. You have simply proved here that science as you describe it is not a very good tool for finding truth and reality. You have rejected evidence before you even consider it.
Remember the old saw of Protagoras who said "man is the measure of all things." And Aristotle taught that the mind can think all things. Put the two and two together and you have Hegel: whose mind is Reason and is infinite divinity.
An atheist could very well accept intelligent design, but instead of pleading God as the designer, he could instead plead sentient extra-terrestrials. A prime example: Star Trek's cheesy post-facto explanation for all those bipedal humanoids is that an ancient alien race seeded the universe. I believe Francis Crick, who won the Nobel for his DNA work, thought DNA was extraterrestrial in origin, though I do not recall whether he believed its source was intelligent.
The facts and logic may lead one to believe that ID is necessary. But belief is not proof, it is just that belief. The facts and logic lead one only to the point where we can say I dont know.
You have simply proved here that science as you describe it is not a very good tool for finding truth and reality.
I dont claim or deny that there may be aspects of reality that science cannot measure now, or possibly will never be able to measure. But the claims of ID are, at best premature, and probably fallacious.
That knowledge has a limit does not require the existence of anything beyond that knowledge.