The point of folk/fairy tales isn’t to be über-original, or show a balanced view of humans, in all their contradictions and shades of good and evil.
The point of these tales is to look at the good and the evil (as represented by the characters), and then to decide what to do with them.
Whether we will encounter evil in this life is not the question. The question is, What will we do with the evil we find? Will we fear it? Flee it? Fight it? Surrender to it?
This is what these tales explore.
Leave the fine distinctions of good in the heart of goblins or evil wizards to those writing for a more “modern” purpose, and let the folk tales do what they’ve done for millennia: personify good and evil, and let us watch how they interact.