I think it was more questioning the methodology - ie. using large jet water bombers at such low altitudes and speeds being inherently much more dangerous than he views as prudent for the situation.
I hasten to add that I'm not a pilot; I would like to hear comments from the pilots on the forum about his criticism.
The huge number of comments on his post was quite interesting, I thought. As usual, some seemed knowledgeable and thoughtful; others ignorant - of both the aviation and the landscape and broadly heathland vegetation in Fitzgerald River NP (ie. not towering eucalypt forest). The park is not really that isolated, but its interior is rather inaccessible by land because there are few tracks.
