Intelligent Design theorists believe that the designer's activity in the universe can be detected. Many Christian scholars, although they believe God to be the creator, reject ID because they hold that there is no way to detect God's activity, at least not in nature. This poses for them a very serious problem which Denyse O'Leary highlights here.
Here is what I think drives that sort of behavior: Some Christians in science are into emotional meltdown re ID because they have suddenly realized what is at stake:
The only way to rule out ID is to deny that God acts in the universe, period. If he acts at all, his action may in fact be detected.
If one insists as an article of faith that God's actions cannot be detected in principle or that it is wrong to attempt to detect them, that is a new article of faith, and one that is at odds with traditional Christian religion and conventional interpretations of the Bible.
but more generally,
For a long time, many fine Christian scholars got along well with materialists, more or less, because no one put the issue squarely, as the ID guys have done. So Christianity in the intellectual world has been dying the death of deniability: What can you deny and still be a Christian? But now the issue is so basic that it can't just be sophistically manipulated out of existence. Gradually realizing their dilemma, in an intuitive way, some sincere Christians retreat into meaningless abuse of ID hypotheses.
It gets better. Read the whole thing.
The main problem, though, for Christians who hold that God's work is undetectable in nature is that they have to deny the possibility of ever recognizing a genuine miracle. If miracles are indeed unrecognizable then no one could have known the miracles that Jesus performed to really be miracles, and thus the Biblical testimony about miracles must be unreliable. This conclusion seems a high price to pay in order to try to seem reasonable to one's secularist colleagues.