I guess you mean that although what I posted is all true, which it is, it does not give credit to the more positive aspects of Australian culture.
I would have thought the same thing some years back. But I am possibly somewhat older than you, and have watched the decline which is now accelerating at a pace...and have also realised that our culture has been in denial about so much for so long. The notion of 'Aussie' is, and to a large extent always has been, a caricature, a cartoon really. Our notion of ourselves was invented in the late 19th and early 20th century by poets like Henry Lawson and Banjo Patterson. The ideals however were mostly a fantasy, which dissolved under the impact of American TV in the 1960s. We don't really have a culture. We have a collection of nationalistic ideals which are really just fabricated nostalgia IMO.
It's hard to respond directly to your original post and this one, so I'll just give you my general thoughts, and we can take it from there I guess.
Culture is always changing. Anyone who clings to ideas of 'Australian-ness' based on historical perspectives is inevitably going to view change as 'decline', since we are moving increasingly further from our 'roots'. That is, simply, inevitable.
Further, we clearly have a culture. It's not 'throw another shrimp on the barbie', and in truth never was. But the cultural cringe involved in how we presented ourselves to the world in the past didn't always speak of a modern or confident nation. In any case, our true culture has always been more complex and less easy to identify than some jingoistic slogans might suggest.
I work with a large number of people who have come here from overseas, both temporarily and permanently. I work for a Swedish company, so majority are either Scandanavians or Sri Lankans, with a few South Africans thrown in for good measure. It's interesting to get an outsiders perspective on these things, but in general they don't have too much trouble identifying our broad cultural markers, both good and bad.
Globalisation does have a tendency to shrink the world and to cross-pollinate cultural identity. American culture obviously becomes pervasive and influential, that being the case. But it's not the first time overseas cultures have impacted on our local culture. And whilst I can understand your age lends you some additional perspective for things I have only read about, it's pretty clear to me that American culture (on the whole) is not aped in the same mindless way it was when I was a teenager. You have your religion as music...consider the local hip hop scene as an example of something which was originally a poor copy of American culture, but which now has a much more local flavour. It's not exactly a new phenomenon for us to follow overseas trends and rules.
Some of the examples you gave (for example, poor treatment of indigenous) whilst holding accuracy, are also not new. These have existed since European settlement. Not to run away from these at all, but they can't be used as support for a declining culture (whatever that is).
And sentences like 'Australia may as well be the 51st state of the US' or 'Australia has some of the most Draconian laws on earth' are pure hyperbole.