In "The StoryTeller," by Saki, what do these words of the aunt mean "You have undermined the effect of years of careful teaching"?

In Saki's "The Storyteller," the aunt is outraged at the
bachelor's "most improper" story that leaves good not only unrewarded, but punished. 
For the bachelor puts an ironic twist onto the aunt's story of the young girl who is so
good that she is rescued because of her moral
character. 

In the bachelor's story, the girl is described
paradoxically as "horribly good" and she is rewarded with three heavy medals which she
wears around her next.  Ironically, also, it is these medals for good behavior that
prove her nemesis.  So, good does not triumph over evil as years of "careful
teaching" have conditioned children to think. This unorthodox method of storytelling in
which good is not rewarded and there is not a happy ending is illustrated in this
passage: 

The
wolf came sniffing among the branches, its black tongue lolling out of its mouth and its
pale grey eyes glaring with rage. Bertha was terribly frightened, and thought to
herself: 'If I had not been so extraordinarily good I should have been safe in the town
at this moment.

Clearly, the
bachelor's story waivers from the paradigm of the classic children's
story.