AUF only represent speafishers and underwater hockey players, not a single dive club or dive shop would agree to them representing scuba divers.
A lot of the diving deaths (snorkelling and scuba) in Australia are tourists. In many cases, they are people who probably cannot even swim and come here to visit the GBR and decide to dive or snorkel, even if they have never done it before (or in the case of certified divers - have virtually no experience).
You only have to go on any of the tourist operations out of Cairns or Port Douglas to see that less than 10% appear to have any real experience of the ocean.
About 20 years ago after a series of deaths in Sydney, the Coroner referred the matter to the relevant Minister and Government department. I went along to a meeting with the department's officers (representing scuba divers - I was president of the Scuba Divers Association of NSW at the time) and they straight up advised that they would not be doing anything adverse as they did not see what they could do to improve safety (our view was that it needed to be much harder to become a dive instructor - experience wise - so that there were not people with just over 100 dives teaching others). Anyway, nothing happened.
Certainly, in NSW in more recent years there have not been that many deaths of experienced divers that have not been easily explained by what happened on the dive (eg one was a medical condition, one was a diver running out of air and over-weighted, one was a CCR who ignored error messages, one was a CCR who stuffed up big time, aone was a CCR who took off CCR in a wreck and became separated from it, another was a very deep dive where the diver appeared to possibly use the wrong mix on way down). Very few have been normal run of the mill dives as far as I remember.
What can be done? Probably nothing, apart from on the GBR ensuring that old and possible very unfit people are advised against snorkelling.