Not sure what history books you're reading, but the history of China is one of imperialism. China didn't just form with its current borders. It expanded and contracted and expanded some more for millennia.
The borders were continuously shifting, but they did stay somewhat near a focal point for centuries.
The US meanwhile has an overseas empire for honestly no good reason.
Highly recommend the book “How to hide an empire” which talks about the American version of colonialism.
China's borders today are essentially identical to what they were...
... when the U.S. Declaration of Independence was first uttered in 1776
> China didn't just form with its current borders. It expanded and contracted and expanded some more for millennia.
As did everyone else?
I don't see China having military bases all over the world and proping up "freedom fighters"