facts. The US is not going to war with China any time soon, but the insinuation that the US could destroy the majority of an active force 2 million strong in one of the largest and most geographically diverse countries in the world without suffering casualties is one of the stupidest things I've ever heard on this website. It's just ridiculous, even if the only method used was just bombing the shit out of everything.
North Korea is another matter. Despite their outdated equipment, they have over a million active duty military members, with a fuckton (1 fuckton= 8 million people) of reservists that would certainly be called up in the event of a major war. They have the advantage of entrenched positions, including but not limited to (fairly outdated) artillery, and fighting in their own country. While it is difficult to know for sure how loyal the average infantryman is to the state, there would likely be fanatical fighting from the North Koreans just because of the propaganda that has been spewed at them about the US and South Korea.
No one thinks that the DPRK would come out on top in the end, but such a conflict would be horrifically costly for both sides.