Sadly, it's not unbelievable at all. It stinks, but it's not surprising!
It's the low and slow season and the island 'low-life' will take advantage of every situation. Sadly, nothing new here.
The article doesn't say so specifically, but I'm guessing these people were alone and that in itself is NOT a particularly good idea, and for sure not in the more isolated locations of the island. Probably not the best time to enjoy some of these more isolated venues - Cupecoy, Happy Bay, Hidden Beach, etc., unless doing so in a group. There is usually more safety in numbers though not always, but it really stinks we have to think this way.