Reminds me a bit of the old line, “Rome conquered the world in self defense”.

The idea that “we acted outside our borders in defense”, is a line as old as empire itself (and in no way unique). One need only look at the changing borders of China over time to see that their interests extend exactly as far as the geography and external kinetic force allow it to.

Another line of thinking they’ll teach you in China is that the people of Tibet were enslaved by a ruling class, and their annexation was actually a liberation for the good of the local population. Maybe they’re right, and maybe five people in Tibet agreed before they started shoving families of Han Chinese into the region en masse, but justification of expansionist policies is a different discussion than whether their policies are or are not expansionist.