The states harmonised defamation laws a few years ago. They are slightly less draconian then they used to be but still a disgrace.
There are a number of legal websites that explain the QLD defamation laws, and it seems clear (to me) that; PUBLISHER cannot wash his hands and walk away. (although there are defences)
It seems certain that if YOU (as an anonymous forum user) make a post that is clearly defamatory,
you are legally liable. (I always believed this to be the case).
Not sure how the court goes about about calling them out, (but note the HC vs Cudeco case)...and others via google.
It is possible in some cases that the aggrieved party believes that an ex-insider is spreading untrue information and they wish to confirm the identity of the person, so they can pursue further action
Interestingly, a motor vehicle forum I am on had this problem over 10yrs ago.
In that case, the situation is that NOTHING can be deleted, even by admin!
The unmanned server exists in Norway, and suing the moderators is fruitless, as they can do nothing.
There rule is unacceptable "commercial" criticism will get you banned.
Suppliers also know that threats to sue will become known via other sources on the internet and would be bad for their business ( as entirely closing the website is the only option)
I note Whirlpool contains quite heavy-hitting direct critique of many, many commercial products, although I am not active there and do not know the moderation style.
Joe is an excellent moderator imo, with superb balance.
When i looked up the protagonist law firm website, a "chat" reply box opened within 10 seconds..Hi
I know Joe cannot comment or encourage further publication, but imo, publicity would not be what the applicant is seeking in this case, they also would not wish for individual persons to ask difficult questions