How is that a good thing?
Its not the first fatality there Saspotato, there have been a few. Initially the landowner took the decision that to dive there you would need to have the relevant qualifications and go through Don Shirley and his school, however as in anything, this was abused, and as its so far from anywhere it was impossible to control. Divers would just arrive and dive, unbeknown to anyone. Obviously there were fatalities.
We have to understand where this dive site is, its very remote, completely isolated and without any form of communication.
Just to get to the water you need to have a 4 x 4 vehicle, take all your requirements with including water,food,tents,air,etc, absail yourself and your equipment down an, I guess, 60 / 70 m drop to the water,dive,and do the same to get back up.
Its not an everyday recreational dive.
The cave is for all (our) intents and purposes bottomless (okay naturally there is a bottom, but its way below diving levels) and the neck of the entrance is convoluted, so in effect you are diving in an overhead enviroment.
As you can imagine, any accident even a minor one becomes a massive issue, as, if you can get the diver out, access to medical assistance (unless you have a doctor and a chamber on site) is at least 6-8 hours away by road, there is nowhere to land a helicopter (even if you could contact one telephonically, and you cant) due to brush and tree growth, so even in an air evacuation you would still need to get the diver out of the cave, up the ridge, carry them to a vehicle and drive to the closest road - I would guess that will take at best 3 hours.
The landowner was (after the Dave Shaw) incident no longer prepared to keep the site open and risk further fatalities, his argument was he risked possible law issues, he felt in a way responsible for the site and he was just a farmer, he could not deal with the standard legal problems, family issues etc of a diver fatality on his property, and hense, closed it off.
Certainly could access be controled and diver qualifications checked before they were allowed to dive, perhaps he would consider re-opening it, but its just not logistically possible, and in this light I think he made the right decision.