It seems fundamentally unfair to compare cases of religions whose people actually committed genocide to religions whose people tell stories about committing genocide.

This is especially so considering the original post here, which points out that people don't actually follow all the commands of their religions and have blind spots about the religions not saying what they say. That applies to stories about genocide just as much as it applies to direct commands--you can reason all you want that someone who believes that fictional genocides were real and justified is as vicious as someone who actually commits genocide, but people's minds don't work that way. It's entirely possible to think Biblical genocides are justified and have blind spots which would lead you not to commit genocide in any real-life situation.

(In fact, I'm not erven sure I could call all the possibilities blind spots. If you believe genocide is only justified when commanded in person by God, is it really a blind spot to say "God doesn't directly speak to anyone nowadays, so I won't commit any genocide"?)