Ok, I'm going to attempt to answer this even though I'm unsure whether your question fits within the rules of the Subreddit.

The answer is that it is political. While most sources will have the start of arguments surrounding what should be taught in Australian history somewhere in the late 80's with people like Geoffrey Blainey, the reality is that it has been fought over for decades.

What your actually referring to is the History Wars, an ongoing debate over what should and shouldn't be taught in Australian schools when it comes to Australian history. There are two sides to this argument, those that support the teaching of Australian history with all of its bad parts (post-colonisation/invasion conflicts with indigenous peoples, exploitation of Pacific islanders, institutional racism etc) and those who think class time would be better spent teaching Australian students about the achievements of Australia and whitewashing our history. While these arguments aren't directly linked to the ideologies of the two main Australian political parties, in more recent decades, Labor has shown a tendency to favour teaching Australian history (both good and bad) while the Coalition has tended to favour the other side of the argument. This has been most clearly displayed with the release of the National Curriculum for the teaching of History.

The new curriculum puts an emphasis on teaching the good and the bad parts of European settlement of Australia (including the Frontier Wars) and the Coalition criticised the Labor government for favouring a Black Armband view of Australian history. Their arguments was that Australian students should not be made to feel bad about their history, especially when they were not responsible for it. When I taught Australian history using the new curriculum I found it to be very balanced with its approach and endeavored to include as much bad as I did good. However individual teachers can choose to teach certain things and leave out others, it varies teacher to teacher and school to school.

The teaching of Australian History could soon change again. The Federal Minister for Education has called for a review of the National Curriculum, mostly because he says there is a bias towards Labor governments while the achievements of Coalition governments are downplayed or left out all together. Australian history is a political football and and will continue to be until education is left to the people who are best informed to determine the needs of students, the schools and education institutions.

Much of the mainstream scholarship was done relatively recently. Henry Reynolds was the premier academic working this field in the 1980s, and he was shocked to discover he was often the first white historian to be looking at the data that he was.

Reynolds' scholarship lead in part to the 'culture wars' of the '90s, a very public fight amongst Australian academics and commentators. On the one hand you have the established narrative (that the settlement of Australia was largely conflict free, because indigenous people were either very few, or not interested in fighting), and on the other hand you had the new narrative pushed by Reynolds and others, that the settlement was contested fiercely by indigenous people, and that tens of thousands of people died in armed conflict.

Reynolds' work gained wide acceptance in academia, but was challenged in the public arena particularly by a writer named Keith Windschuttle, who wrote a book called 'The Fabrication of Aboriginal History: Volume 1 Tasmania'. In it he argued that oral testimony from indigenous people was unreliable, and that key white characters in the past were biased towards telling a story that white people were treated aboriginal people terribly.

Windschuttle's book was torn to shreds by the academic community, but was very popular amongst centre - right (and plain old hard right) politicians and media outlets. This lead to the public perception that the issue was a matter of academic debate in much the same way as the climate change debate is viewed.

We're going to run into the problem of the 20 year rule and perhaps soapboxing here, but the reason as to why the dominant narrative (of a largely peaceful settlement) wasn't more heavily pushed in the curriculum has to do with the politics of the government of the day.

So yeah, read Reynolds, read Windschuttle, read the short book published in response to Windschuttle if you want the long of it.