I don't want to get into a debate about religion, but in some people's beliefs, any association with magic is to be avoided (it all comes from the devil or whatever). I agree that it was probably not intended to apply to fictional works. I guess the thinking there has become that if the children accept magic in fiction, they may be inclined to pursue the real thing as well.
As far as educating the children, in most cases like this the parents can't do that because they are not educated on the subject either. They would have to become educated on it first... but then, that's against their beliefs, too. It's a catch 22.
