Christian doctrines as incentive/support for more basic beliefs?

In my previous post, I mentioned that the Gangadeanians sometimes speak as if their theory of knowledge is correct or at least that the kind of certainty they equate with knowledge is attested to by certain Christian doctrines. When faced with the challenge of differing accounts of the nature of knowledge, they sometimes respond with, "well, fine but the kind of knowledge I'm interested in and the kind of knowledge that we ought to have regarding God's existence, is absolute certainty." And I pointed out how this seems to be a fallacious move. This move depends on presupposing the bible (or at least particular segments of it) to be true. For example, the thinking is that not-knowing God leads to maximal consequences, and so it must be maximally clear (knowable with certainty) that he exists. But the issue of which theory of knowledge is correct, and what kind of knowledge (whether absolute certainty or not) we ought to have with respect to our most basic beliefs, is logically prior to beliefs about whether the bible is the word of God and thus offers any divine insight. So you've got to answer the more basic ones first, and not refer to the less basic issues to support claims about the more basic ones at least unless one thinks this kind of circular reasoning is perfectly acceptable. This has gotten me thinking about certain conversations I've had with Gangadeanians during my departure from the congregation.

When I raised challenges or objections to core doctrines of the church, that is, on matters that they deemed to be most basic, I was sometimes met with the following response. "You know, if you go down that path, you will end up eventually denying Christianity."  Further, on more than one occasion, I've heard Gangadeanians point out that persons who had similar questions as I did, eventually ended up in "bad places" where bad places meant walking away from the faith. The more I think about this approach, the more I think it's entirely illegitimate in just the way that I highlighted above. It sounds a lot like appealing to the bible and Christian doctrine (which are comparatively less basic) to support more basic issues---the very issues that are logically prior and supposed to provide the basis for the less basic issues. Perhaps it's also an appeal to fear.

Any way you cut it, one ought not to evaluate my objections on the basis of what they imply about the Christian faith, the veracity of scripture, lifestyle and the like. This is because my objections are more rudimentary---they have to do with issues that are logically prior to whether Christianity as a worldview is a cogent one. Indeed the kind of move that I'm speaking of actually sounds like a very different kind of presuppositionalism from the kind that Gangadean endorses, namely, the kind that takes the tenants of Christianity as the starting point of all inquiry. To forget about this and to allow for the kinds of reasoning I am calling into question is to lack intellectual integrity, at least by Gangadean's standards. But this is just the sort of thing I've heard from more than one Ganagdeanian on more than one occasion.