There is zero justification for US intervention in Korean War and splitting Korea into two part.I try to sound it differently :
Korea was partitioned into to country, south and north , north started a civil war to reunite the country, and the USA jumped into the face of the North, killing few million civilians in the process, and levelling all building in NK.
So, what is the justification of this ?
Why Russia actions supporting one side in a a civl war different from the Korean war ?
What is your point? That Russia is not an imperialist because US is an imperialist?
OR, how about: "China is perfectly correct to support one weaker imperialist (Russia) against one stronger imperialist (USA)" ?? This is also correct strategy which I 100% support, because it acknowledges reality of Russia's brazen actions and acknowledges the realpolitks of Sino-Russian alignment. These are not mutually exclusive, China can support one imperialist against another. It's one reason why China is neutral at UNSC.
I agree 1000%. Once Taiwan is reunified, then China can perhaps drop the "non-interference in internal affairs" principle, but no way to drop it now just to support Russian adventurism.The current stance of China of remaining neutral with respect to the current Russia VS NATO/US confrontation in Ukraine can be partly attributed to the fact that China isn't yet ready to fully commit and go all out in supporting Russia due to her economy, military, technology, education etc.. not fully optimize a.k.a. Insulated from external forces if it were to openly support Russia. China fighting at a disadvantage by choice is counter to it's strategic aims and objectives not to mention the political viability, stability of the CPC would be severely damaged if it were to fight and lose along with it all the consequences of failures. And one thing that's consistent in Chinese history is whenever a major upheaval happens or occurs they are almost always followed by the collapse of a dynasty.
I agree with most of the points you raise not for the same reasons you laid out but for the simple fact that China is simply biding it's time not to mention that its utmost strategic priority is Taiwan, everything else is of secondary importance.