Honestly it sounds like you're just coping by suggesting this argument:

Imperialism is the main contradiction of our era. China presenting a viable alternative to US/European hegemony and helping to usher in a multipolar world is a major accomplishment that will improve global wellbeing.

Isn't:

Rational- it is, the argument is based on an understanding of anticolonial and multipolar theory. If you'd like to learn Id suggest starting off with "wretched of the earth" and "imperialism the highest stage of capitalism" before moving on to more modern stuff

On topic- you were complaining about China doing bad shit without getting into specifics, I said "yeah, like (examples of massive accomplishments)" and then I mentioned that they were helping erode a unipolar imperialist system. I think helping to erode a unipolar imperialist system is a big accomplishment and fits into the topic.

Good faith- I don't see how I've given any indication that I'm not being earnest in my beliefs.

Moving goalposts- i really don't know how to respond to this, where do you think I initially placed them, and where do you think I moved them to?