Interesting question and point as always, Roomie.
Just sitting @ my keyboard, enjoying an espresso, while Mrs Ozzie soaks in a bubble bath, here's a few thoughts:
1. JWs in Australia have a long history. They were one of the first places reached by the followers of C T Russell and establsihed a depot in Melbourne. In those times, the "organisation" was established here with some British roots. The name was the British one of IBSA (International Bible Students Association), and Australia was, at that time, a British colony. That being said, the response was, and still is, quite unremarkable.
2. Australia has a strong Catholic heritage and, as we know, there is a great response among Catholic folk to the JWs message. (Similarly, they both proclaim salvation by works.)
3. Australia has grown with an individual culture that is part-American. We even had a Prime Minister who proclaimed "All the way with LBJ!" Well, Australia is very receptive to anything American, like entertainment, etc. On the religious front, there are a number of American-based religions/churches here.
Just a few random thoughts.
Cheers, Ozzie
Freedom mean not having to wear a tie.