But why China specifically? Why not wield this power to improve Saudi Arabia for example? (note that since the Saudis are allied and deeply rely on the US, it should be easier to sway them into doing good)
There are a variety of reasons proponents of changing China could make in response, for example since China is becoming (already?) powerful independently from the United States which could (already?) makes them a greater threat, having our opponents share as many values as possible would be ideal in a multipolar world order. However, I'm not arguing for that position, I just don't understand the idea that because the United States has failed on X, Y, or Z issues that that means we shouldn't try to solve those problems whenever they appear. Does that make sense? I can give clarification if needed.