system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: I'm watching 'Grave of the fireflies' at the moment and I'm curious why the US Nuked a city and not a military complex.

Thanks guys, I wasn't trying to be 'controversial', just wanted a few facts to go with the movie.
gpt
* By the end of WWII, the bombing of population centers as part of a total war was an accepted practice (see: London, Dresden, Tokyo). As many as 2 million Japanese civilians had already been killed by conventional bombing by the time the atomic bombs were dropped

* Around 20,000 of those killed in Hiroshima were soldiers

* Kokura, which had a much larger military establishment than Nagasaki, was the original target for the second bomb.