The US bombed and firebombed until there were “no more targets in Korea.” https://en.wikipedia.org/wiki/Bombing_of_North_Korea Examine the primary sources if you like, they’re decent. It was comparable to genocide.
And now we point and laugh at the DPRK for being less developed than the US-backed South?
Your understanding of Chinese infrastructure isn’t rigorous if it’s entirely based on some sensationalist viral videos of some places which look bad. Yeah, it’s a massive country with a billion people, some of those places look bad in a video. I’m not happy about the bad construction you see there, nor the real estate speculation causing some of it (which isn’t a communist feature).
You can find lots of videos of places in the US and Canada looking bad too, only it’s like cops destroying the tents and property of unhoused people in the streets. But in response to those we might say “oh that’s terrible, they should fix that” and not the “we gotta overthrow the authoritarian government” when it’s about China.