There is nothing in anything I have read that would suggest that the teachings of Mary Magdalene have anything to do with what the Sister's of Mercy did in her name. "Mary Magdalene is sorry for everything that was done in her name" The Mary Magdalene Character - the flawed shamed mad woman only important because Jesus forgave her - has become a trope for many men writing women in stories ever since. There's even reason to believe that Shakespeare based Ophelia on her!