Does it matter? Whatever someone's reasons are for supporting China, the important thing is that they do. Results are what matter. The fact that millions of people around the world have a positive view of a prospering socialist state that is currently the biggest threat to the global imperialist hegemony is conducive to our goals as Marxist-Leninists and anti-imperialists.
In general i care less about why someone does something and more that they do it.