The reason for the dark storied in the original fairy tales is to teach a lesson, to stand as a warning for children intimidated by them. There is so much educational content in them which Disney cut out, stripping the tales from their original purpose. That’s (one of the reasons) why I hate Disney.
Similar situation in South Tyrol (an province at the border to Austria): the german-speaking minority (who is the majority in the province) primarily uses italian curse words. A theory I once read trying to explain this is that you hope that God is less likely to notice you when you curse in a different language.