When Europeans first settled in Australia in 1788, they encountered an Aboriginal society of almost incredible barbarism and violence.
This was the reality of what they found.
The reasons for the violence and barbarism of Aboriginal society derive entirely, or almost entirely, from one factor alone.
All of the Aborigines of Australia were hunter-gatherers who had not domesticated livestock nor grown crops for food.
As a result, the lives of the hundreds of small tribes that constituted Aboriginal society were engaged in a never-ending struggle to find what food they could from what little existed on this continent.
Directly because of this central fact, it was absolutely necessary to keep the size of each tribe small enough for its members to be kept alive by what food and other sustenance they could find.
It was therefore absolutely necessary for them to avoid adding any excess mouths to feed to the limited numbers who could be kept alive by the methods of hunter-gatherers in the Dry Continent.
They did this by systematically eliminating the excess mouths.