Your prejudices are showing. I have known plenty of people who accept the Documentary Hypothesis who are not suspect in their theology at all. Fundamentalism has largely rejected the Documentary Hypothesis, for a few decent reasons and more than a few poor reasons.
I have no great love for the Documentary Hypothesis, but it does draw out the reality that the Pentateuch has plenty of textual evidence for multiple authors and editors. People can take that idea and run away with it to create all kinds of poor theology, or they can take that and come up with good theology. As far as I'm concerned, we have received the texts in a certain way and they bear the internal and experiential hallmarks of being inspired by God. While careful review of the texts and acknowledgement of the realities that may not be apparent to English readers of the scripture can be helpful, they do not change the fundamental realities of the theology that can be learned.