(firebombing was in effect since 1942 on major German cities).
War has never been a place for ethics, ashing thousands of (civilian) people and claiming to save humanity is a fucking joke.
It didn't work either, because Japan had to be nuked twice afterwards.
“Dresden, the seventh largest city in Germany and not much smaller than Manchester, is also far the largest unbombed built-up the enemy has got. In the midst of winter with refugees pouring westwards and troops to be rested, roofs are at a premium. The intentions of the attack are to hit the enemy where he will feel it most, behind an already partially collapsed front, to prevent the use of the city in the way of further advance, and incidentally to show the Russians when they arrive what Bomber Command can do.” RAF January 1945