I like the article. Personally, I do have a convict background on one side of the family. It was hidden from the family for more than a century. About 20 years ago it actually became fashionable to have a convict forebear. It doesn't fuss me one way or the other but it is interesting to do the research. In competitive terms as an Aussie, I hate to see our athletes beaten. (It's ok if a New Zealander wins occasionally, but not if it's a one on one contest.) It's never ok for the Poms to win as the they are the traditional foe (unless of course they beat the French or the Americans). It's not ok for the Americans to win either, except for Tiger Woods, 'coz he's pure class.
As for wiping your **** with the national flag ... it depends whose doing the wiping. If it was an Aussie and in the spirit of the occasion, fair enough. If it was a foreigner ... probably a different story. If I was in America, or any other country for that matter, I wouldn't dream of showing disrespect to that country or its people.
I have travelled reasonably widely including 3 times to the US and never encountered any animosity towards Australia, or Australians. Mind you, I'm not sure most Americans are even aware there is a place called Australia!!
I have never met an American who was not polite, gracious and friendly. So what's the beef against the US? Well, as a country they are not that friendly. We had our wheat export market threatened some years back, not by direct competition but as the US giving 'AID' to our trading partners in the form of 'FREE' wheat because the US had a surplus. Our manufacturers try to have a free market culture as is espoused by the US but in practice the US gives its industry massive protection in the form of subsidies, in particular against Australian steel. With friends like that we have no need of enemies!!
The last sentence of the OP article sums it up though. "We don't boo Yanks because they are better than us. We boo Yanks because they think they are better than us."