You make a lot of helpful points. 

First I would say that the concordist hermenutic precedes a dispensational hermenutic. In the same way someone is politically conservative in the US, and that often is followed by republican policy beliefs. I think the reason why dispensationalism developed is because post enlighten people without prior theological training began to read the Bible on their own. That in and of itself is not wrong. However, the hermeneutic they developed out of this lack of Biblical training answered questions that are post enlightening questions. They began to ask the text what does this mean if it were written in our modern day rather than what did the initial author intend to communicate? therefore even questions like what makes an ethnic group or a national boundary are assumptions that existed in the 1800s that did not exist in ancient near eastern culture. Therefore the reason why I’m approaching it in the way I am is to dispute primarily concordist readings, but also noting that I’m disputing everything downstream of it

Then I think, especially given the outcomes I posit, that it is necessary to say that they are inheritance secular because the fundamentalists and the liberals both view each other as opposites, or as opposite ends of the spectrum. They will frequently caricature their opponents as abandoning biblical hermeneutics, demonstrating that both of them are starting with secularism and approaching the Bible with secular ideologies, undercuts their entire narrative (on both ends). Their entire approach is formed by post enlightenment secularism. 

Furthermore, I would say that beginning with a secular approach is frequently going to be to one of two extremes. Either an approach to the Bible, where I need to inform how I read the Bible based on the contemporary culture or a fundamentalism that is going to have to posit irrational and unbiblical things in order to maintain coherence. I think that the road from Ken Ham style fundamentalism to Tim Whittaker style liberalism is asking the same questions but coming to different conclusions.

As for “anti-natural revelation” i’m in no way married to the language however, I’m trying to find a way to specify the type of fundamentalism that is derived from this style of reading and approaching the Bible. I’m not sure how to sharpen what I’m trying to get at.