Why do people suspend disbelief and accept fairy tales as told in the Bible, yet accept that other, non-biblical fairy tales are just that, fanciful tales made up to entertain and/or teach a lesson?
Take Jonah and the whale (big fish - whatever). Fairy tale. Yet people actually believe it because, well, the Bible tells us it happened.
Now take Jack and the Beanstalk. Does anyone really believe that it happened? Not unless they think Abbott and Costello movies are documentaries.
So, if the Jonah story was told independant of the Bible...just a tale handed down through the ages, would you believe it? If Jack and the Beanstalk were preserved in Holy Scripture would you then believe it?