OK, I really haven't read that much about it, so I really should keep my mouth shut, buttt........
In that country, American girls are considered slutty.
And like JW's when you think another person or culture has lower morals then you do, you start immagining all sorts of ridiculos behavior that just doesn't happen in real life.
For instance JW's often believe that worldly people just all have sex with one another willy-nilly, no holes barred (sorry for the pun).
I think that's what happened to Knox and her boyfriend.
Because what they are accused of just doesn't seem "right"