Religion is fiction, but since some people dont agree with that, and that hurts sales, it has its own section. Fiction is still technically an accurate term.
Furthermore, if the store owner wants to put it under fiction, then fine. That is his call.
"We ain't a sharp species. We kill each other over arguments about what happens when you die, then fail to see the ******* irony in that." - Justin Halpern
“We do not believe any group of men adequate enough or wise enough to operate without scrutiny or without criticism. We know that the only way to avoid error is to detect it, that the only way to detect it is to be free to inquire. We know that in secrecy error undetected will flourish and subvert”. – J Robert Oppenheimer.