China wasn't expansionist, though. They never grew much beyond their current borders. They were good trading partners, but didn't have the complexity and drive of the middle eastern civilizations, from the early Persians through the Ottomans.
China was extremely expansionist. It's just that over time they successfully assimilated (or suppressed) most of the regions they conquered, to the point where they and most other people think of them as naturally part of China (ignore what the Tibetans, Uighirs, and Mongols say, they're just disloyal).
That's a bit like saying, "The US never grew much beyond its current borders, so it wasn't expansionist."
(I was under the impression that the true center of civilization was China.)