I had the uncommon privilege of attending a year of high school in Japan, and rest assured there is no lack of propaganda in other countries' schools, even if often by omission of truths.
I am not Australian, but I suspect high school textbooks are likely less than entirely forthright about sensitive subjects like Residential Schools and their role in settler-colonialism.
In total? Sure. But 99% of that propaganda isn't targeted at, seen by, or relevant to, any given person. Can you name one propaganda campaign on social media that is targeted at Australian schoolkids?
The propaganda in schools is highly relevant, exactingly targeted, and (by merit of being literally taught to every schoolkid) always seen.
And if you don't think that the worldwide backlash against "social media propaganda hurting kids" despite social media being around for 30+ years is possibly more than an organic and earnest and uncoordinated concern, I think you may be more susceptible to propaganda than you think.
It's still somewhat the case, but the propaganda in schools outside of the USA is much less than the propaganda on social media.