These people aren't mentally ill, just very gullible.  Most of what they reference, they have not witnessed for themselves, just read about from other FEers.  So they pass on these legends from gullible person to gullible person.  Also, they are philosophically unable to accept the truth.  They believe the Bible is inerrant and they believe it says that the earth is flat.  To accept that the earth isn't flat would be to totally reject there religious faith.  Sad, a fable based on writings by primitive Hebrew scribes 4000 years ago, scribes who wrote an account consistent with their primitive understanding of the world, is now unchallengeable.