Firstly, this Melbourne Age piece is syndicated from The Telegraph, a British newspaper from my home country. As a regular visitor to Australia, with relatives living there, I had presumed that the article was syndicated even before I reached the byline. This due to a clarity of language unusual in locally written newspaper articles.
It sounds atrocious, the treatment of your wife, and if her treatment was as widespread as I'm inclined to take on trust from what you say, then I'll need to reassess a thing or two.
Australians know virtually nothing about Americans as people, and that's a pity. Their television is acutely americanised, and their culture inculcated with American influence, but I've noticed that hardly any Australians have actually met an American. It's hardly polite or even civil to blame the rare American they meet for the perceived wrongs of the US body politic. And I can empathise with your experience somewhat.
It can be parochial. I watched Grease the movie on Australian TV recently, and it reminded me that Australians love John Travolta because he loved Olivia Newton John, who's really a Brit anyway. He's in if he can say g'day. On the other hand Mel Gibson was Aussie and became American. He's not claimed anymore.
But I haven't found hate as you appear to have. Australia is a lot bigger than the left wing inner city self styled intellectuals you apparently met too many of.
Go to country NSW and they all dress and sing like Chet Atkins.