What did Montessori actually speak about Fairy Tales:
"Now, everyone who knows my name says that I am against fairy tales. Apparently I say they are dangerous to a children's mind.
But you must know that I never assert anything that I have merely reasoned out, because if I did that it would just be a theory of no importance. It would be just a matter of opinion and therefore not a serious statement. Serious statements must come from observation - this is the truth. I have never before given an opinion on this subject.
So, if I were against fairy tales, it would not be because of a capricious idea of mine but because of certain facts, facts observed many times. These facts have come from the children themselves and not from my own reasoning. (she goes on to describe following the children's truest, deepest interests and choices - choices for valuable work that led to a leaving behind of certain negative qualitites) The great love of fairy tales disappears too. (continues with the children walking away from fairy tale stories) This shows that children listen, or at least the older ones do, but inside they have more important urges of nature. So we do not see complete interest. If they are free to do something else, children will choose something that is more important to their development.
(The 1946 London Lectures Lecture 26: Truth and Fairy Tales)