A proof of concept for the flag i want in my dorm
This speech is inherently atheistic to me. Firstly, “before what god?” can be interpreted to call into question the existence of a god to oppose or offend. Or it could be interpreted to question which of the many possible deities Francesca would be referring to. This acknowledgment of polytheism would invalidate her implicit use of "blasphemy" as a universally recognized wrongdoing under a universally recognized, capital G, christian "God." Though most obviously the line just exists to introduce the rest of the speech, like "Okay, lets examine the figure you're basing your morality off of here."
Then, yes, he acknowledges the existence of that god. But he is likely doing so in much the same way that I acknowledge the existence of Herbert West from classic 1985 horror-comedy Re-animator. That is, as a fictional character. Even then he refers to Him hypothetically, saying "a god" instead of "God" or "the god" (capitalizing the H, not in a reverent religious way, rather because I respect His neopronouns).
As he continues in talking about the failures of this god, I read it as him simply entertaining the idea of a higher power to criticize it. And I think we can be pretty sure he doesn't actually believe in that god since he exclusively refers to Him as "your god."
Furthermore, yes i said furthermore, I imagine Herbert as a very purposefully atheist character since I believe in the original books he was intended to juxtapose Dan/the narrator's religious viewpoint with an analytical and scientific one
Also, since “god” is used here as a class of deity and not as a name, I feel it should technically not be capitalized. But I tried it that way and I felt it removed a level of drama.