This is an argument you hear frequently. Everyone has methodological presuppositions, including methdological naturalists like Bart Ehrman. Craig Blomberg responds to the charge that his teaching at a seminary that requires an inerrancy statement makes his work biased, in a comment on Debunking Christianity.
Hi John. Good to hear from you again. There are, of course, other possibilities about people like me, which are sometimes, though not always, the case. I was raised in a liberal Lutheran environment and went to a liberal Lutheran liberal arts college that held the mainstream critical views you describe. I then went to an evangelical seminary and then to a Scottish university (largely secular but with some Christian presence) for my doctorate. I did "crazy" things while there like decide to follow what I discerned to be the New Testament model and be immersed as a believer in a Scottish Baptist church, cutting myself off from being able to teach in contexts that required me to affirm the legitimacy of infant baptism. It was also where I finally decided that I could believe in an appropriately nuanced form of inerrancy after having been raised in an environment that held "biblical inerrancy" to be an oxymoron, going to a seminary where it was part of the very definition of evangelical and then becoming familiar with the British evangelical scene where it was viewed as a rather uniquely American shibboleth. So I don't believe in inerrancy because I teach at a seminary that includes that in its statement of faith. I teach at a seminary that includes that in its statement of faith because I believe in inerrancy. And I have had enough invitations over the years to teach in places with different perspectives that I hardly feel constrained in my scholarship by that conviction. I examine every new issue relevant to the topic that I become aware of (though I haven't run into very many that weren't already on the landscape during my three degree programs in the 1970s and early 1980s, just in repackaged garb) and if I should decide I could no longer affirm inerrancy, I will go teach at a place that doesn't require it. As for going wherever reason leads, how open are you to returning to Christian faith should reason lead you there? From my now fairly extensive reading of your published and web writings, my sense is "much less so than I would be open to changing my views".