So, a distinction has to be made between naturalistic evolutionists (Darwinists) and non-materialist evolutionists (IDists / Theist-evolutionists)
Well, this raises a couple of questions.
1) I'm sure you've discussed or heard the distinction between methodological naturalism and ontological naturalism - your argument presupposes that these are perforce conflated.
What evidence have you that they are ?
2) "Non-materialist evolutionist" still covers a lot of ground, and would seem to include characters as diverse as the Buddhist evolutionist, the Catholic evolutionist, the Unitarian evolutionist, and some categories of agnostic non materialist evolutionist.
Yet, ID as constructed by the Discovery Institute types seems to be pushed primarily to advance an Evangelical Protestant agenda, with a few Catholic fellow travelers overly influenced (IMHO) by Evangelicalism.
Why this lack of philosophical diversity ?