In the article recently published by mumsgather on her blog, Mothering times, she wrote about the importance of choosing the right books to read for bedtime to our children. The article, Mothering Times: Choose your bedtime stories carefully, aptly explained that certain stories, like Hansel and Gretel, do bring out the disturbing perception, (among the more perceptive children) that the father may not be looking after his children well. For that matter, so does the story of the Ugly Duckling when even the mother duck reject her 'baby' whom she considered ugly! Mumsgather pointed out that her children were rather disturbed by these stories and rightly so.
I suppose in dealing with situations where we inadvertently bring out the rather unpleasant aspect of certain traits, the best we could do is to use these examples as opportunity to teach them the 'right' thing. My little Dan was quite upset as a toddler when I read him the 'Ugly Duckling' as he felt sorry for the little duck which was left alone. He cried afterwords but I explained to him that he should be nice to everyone and not leave them out because of how they dressed or looked. I remembered him wiping his little eyes afterwards and was quite determine to do just what mommy had told him. ;)