The debate about what is a night VFR has been going on forever.
Many do not even understand what is real night flying because nobody teach you what it is to fly in pitch black area and deal with all black hole illusion you will face.
Until you are in those situations, it is difficult to understand how hard and dangerous it is.
Any night flight done outside lit area is an instrument flight. We don't have to call it an IFR flight, but procedures are required to make sure you do not get caught and unfortunately, it is very easy to get caught.
It will be interesting to see what kind of procedure they were following in this case.