I really don't. Because it's a fantasy world created by a writer, and that writer is from our world.
"I wrote a story about fucking kids, but it's okay, because it's about fantasy world where it's okay to fuck kids." wouldn't fly.
"I know it was inappropriate, but I didn't want them to be sad" doesn't seem like it'd hold up either. It's not telling them they can't have a cookie before dinner.