James has some excellent commentary on the Reppert / Exbeliever exchange:
Reppert: "EXB is just begging the question here."
This is exactly right. EXB's claim that AFR fails on account of the prior implausibility of theism is just an attempt to bypass the substantial philosophical issues on which AFR trades. Moreover, even if EXB were correct regarding the plausibility of theism, isn't it evident that even an implausible worldview that can account for the preconditions of human reasoning is rationally preferable to any worldview that undermines those preconditions?
As for EXB's materialist narrative, he is essentially claiming that the laws of logic supervene on biological facts, specifically, facts about the origin and structure of our brains ("logic supervenes on this linguistic biology"). But then it follows that the laws of logic are merely contingent rather than necessary (since all biological facts are contingent facts), and merely descriptive of human thought rather than normative for human thought (since biology is a purely descriptive discipline). Indeed, EXB states as much: "I would say that logical laws are how we think..." (emphasis added). That is, EXB holds that the laws of logic are concerned with how we do think rather than how we should think; and what we humans take to be 'logical' or otherwise is effectively an accident of our evolutionary history.
Such conclusions place EXB squarely in the camp of Rorty and other epistemological anti-realists. If this is the philosophical fruit of materialism, EXB is welcome to it. But I'd venture that it does little to enhance the plausibility of materialism vis-a-vis theism.