This is applying post facto knowledge to a decision when assessing it ethically.

to some extent, sure, but top US military officers believed that Japan was on the verge of surrender and I doubt they kept this to themselves

It always comes down to this. Chinese lives don’t matter, Korean lives don’t matter, Soviet lives don’t matter. As long as the precious Fascist civilians get to starve to death instead of being bombed, or conscripted into a kamikaze mission, or shot for dissenting instead, it’s aaaaaalllll worth it!

they weren't "Fascist civilians", they were civilians in a fascist country; this was intentional mass murder of civilians, not just accidental casualties caused by attacks on military targets