Except that this was so clearly the opposite of being in public, and that the laws in the country they were in at the time are incredibly strict. It is a super-secluded estate, and the photog used a VERY, VERY long range lens to capture the image whereas to the naked eye they would not have been seen - especially without setting out to purposefully disrupt their privacy to capture a photo of this nature.
Right there is where your argument fails. My, my, the Katiettes just happened to pose at that precise spot at that precise time.