There is literally no way you can justify the extent of the bombings that America did to North Korea during the Korean War, during which South Korea and America were by far the worst offender of civilian casualties.
America supported and assisted the brutal regime of Syngman Rhee whose army and police had predominantly collaborated with Japan during their occupation in WWII, and if you know about the history of Japan's dominion over Korea, then you'd understand why this was such a sensitive point. Thus, it's worth remembering that the precursor to the North's invasion was a rebellion in the South, and there was a lot of Communist sympathy throughout Korea. It's easy to just paint the North right now as the bad guys because of their horrific regime, but the history is a lot more complex, and America have certainly never been the good guys.