As they themselves have pointed out, they're still in a primary state of socialism where the main objective is the development of the productive forces. Due to the scale of china, their cultural context and past socialist projects experienred they considered that a market economy is the way forward for them, when it no longer makes sense they will advance into a new system.

In a nutshell, China is communist because the political power is solely focused on the communist party, whereas in the rest of the world political power is in the hands of capitalists. You won't see a BYD executive dictating policy in China, whereas in the US you will see Jeff Bezos and other oligarchs acompanying the president to diplomatic meetings.