That really pissed off a certain community:
I understand a construction worker feeling pride in their contribution to a building, or railway. However the physical construction is such a small piece of the overall process; it's a contribution, not the entire thing. "America was built on slaves", is akin to saying skyscrapers were built by construction workers while forgetting that the construction workers themselves alone can't build the skyscraper; they need the contributions of the entire economic hierarchy.
It's a similar deal with the repeat argumentation we see here of "we were the greatest then we were colonised, it's the colonisers fault we are behind now, wait and see"; is a non-sequitur response that feigns ignorance of if they weren't behind in the first place, they wouldn't have been colonised; they would have been able to defend themselves and protect or leverage their resources for internal use or external trade, like other civilisations were able to: colonised countries had underutilised resources from underperforming economies that other countries needed more to prevent greater harm; colonisation is expensive, it only makes sense if profitable/viable, and furthermore there is no need for it once the system underneath had been supplanted with capitalism unlocking international trade with the empire; myths of revolutions and freedom fighters don't change economic practicalities.
Same deal with slavery, slavery ends en masse once an economy is no longer necessitated upon unskilled labor and starts unlocking educated labor instead, making slavery optional, unlocking a new moral question of slavery.
Same deal with vegetarianism and veganism, they open up as alternatives only once the economy unlocks them, then the moral question arises.
Morality follows the economics. Unavoidable necessary harm happens until the system evolves to a point where a harm can become unnecessary and avoidable; a choice. Before it's a choice, traditions even perceive such harm as sacred (without question) and pure (without alternative) and consequently compassionate (without ultimate harm).
That said, the average Australian is also ignorant of the imperatives for empire; they are just haemophiliac bleeding hearts to the useless with no philosophy. There is no practice of steel-man debate in Australia, so no one there has contrasted positions.