That's the problem debating creationists -- lack of understanding of what a scientific theory is.
If you want proof, get into math. Otherwise, you're not going to find it in a scientific theory.
but all of a sudden, when proponents of intelligent design infer intelligent design from organized matter (circumstantial evidence)
ID doesn't even qualify as a scientific theory. All you have are untested hypotheses and a series of usually unscientific attacks against an established theory.
There are rules to science, and they are vicious. It's a dog-eat-dog world out there. Don't feel bad if your "theory" gets thrown out and relegated to the quack fringe, because it'll have a lot of company that isn't even religious-based.
If all a theory needs is circumstantial evidence in order to be scientific, then you have no business disqualifying intelligent design as a scientific theory. If it requires more, then the theory of evolution is not qualified to be called as such.
If "proofs" are the sole domain of mathematics, then why get one's panties in a twist when reminded that evolution (in the wide sense) is a theory as opposed to a proven fact?
ID doesn't even qualify as a scientific theory.
It does if held to the standards required by evolutionists for their "theory." Furthermore, intelligent design enjoys thousands of examples for direct observation at any given moment where intellect is at work. That's more than one can say for what is essentially a philosophy of history concocted by the imagination based upon the assumption that where there is a common form there must be common history.