The impression that you give hear on FR is someone who has some claim to make against everyone interested in intelligent design. I'm not educated on what all those interested in intelligent design think and do. Some of them may just believe that evolution alone is not capable of explaining things or that they see intelligence behind things and have no interest in confirming a religious belief. They may be out to prove what they believe but that's where a lot of science starts. Even Darwin was acquainted with Evolutionary concepts before he went on his voyage and he did not come up with it entirely from his research. I'm wondering if questioning the motives of all of them is fair. But, like I say I don't know all of them or any of them.
Once again, I'm going to accept your point here--it can get dangerous to assume 'motivations'.
In partial mitigation, I would invite you to make an analysis of a few of these evolution/creation threads. It is rare (and I think it can be demonstrated) for someone arguing the Creationist side to engage with issues of science, but it is (sometimes tediously so) common to find someone on that same side object to evolutionary theory solely on the grounds it is contrary to some specific reading of Biblical Genesis. And I have yet to hear anyone propose, from the other side, that they hold evolution to be more probable on the grounds that it is superior on theological grounds.
Religion is religion, and science is science. Science cannot, and does not seek to, address supernatural matters; why do some religiously-minded folks ask it to validate what they hold to be spiritual truths?