I'm not using my stories to preach, but I do write about ordinary people with ordinary faith and the ordinary practices of that faith. I don't have a problem seeing salvation on the other side of the monstrous apocalypse, but I recognize that others may. The same problem extends to many other settings and sci-fi conventions where humanity has left Earth behind for the stars, fantasy realms where the Earth is completely different, or worlds where Earth and humanity are not a part of it at all.
1) fiction is metaphorical communication concerning the "human condition"
2) the most pressing problem of the human condition is the need for recognition of sin and a savior therefrom
How do you effectively communicate in a setting (like Star Wars, Star Trek, Dungeons & Dragons, or Atomic Earth) where the consumer may perceive that God does not or cannot exist?