We kept China from getting their assets handed to them by Japan in ww2. Less than a decade later they ensured we would hhave no victory in the Korean War and forced us to fall back and Establish the 38th parallel. Bunch of traitors and ingrates. I hope they fail and their economy collapses. All the products they manufacture are shoddy anyway. I will gladly pay more for better goods and watch their country fall apart.
On the first point:
You really don't know your history. Japan took advantage of China when it was embroiled in a Civil War that started in 1927. Japan officially started war with China in 1937 after the civil war had claimed 2,000,000 military dead. There was a temporary ceasefire between the warring factions (Republic of China and the Communist Party) but they still were separated but against a common and greater foe.
China was bested by the Japanese early on but weren't losing
by any means as by 1939 they were at an effective stalemate. 1941 and further just weighed the odds in the Chinese favor as the US started pushing against Japanese assets in the Pacific.
Losing battles early on is not an indication of overall strength. We lost Kasserine Pass pretty damned bad against the Germans and lost Coral Sea pretty bad against the Japanese. As well as the various other holdings throughout the Pacific. It took our burgeoning military the better of mid-1943 before we actually had the Japanese on the ropes. It was obviously another full 2 years before they were defeated.
Regardless, as soon as the war was over the Chinese were right back at their civil war. We backed the Republic of China under Chiang Kai-shek who were fighting the Peoples' Republic of China (communist) under Mao Zedong. The PoC were overwhelming in the early parts but lost favor and strength as the Soviets bolstered the PRC.
So, the government that opposed us in Korea and afterwards is not the one we helped out at all. It's like a European saying "We helped the Confederates in the US Civil War. How dare the US Government not be our undying friends decades later!!!".
But I agree with your other points. I'm exceedingly wary of China and the threat they pose to Pacific Realm stability as well as their manufacturing and education standards being very spotty at best.