I personally knew two Filipinos who barely escaped that atrocity. One was supposed to take a boat with his unit from Manila to Bataan province (it’s not far as the crow flies across Manila Bay), but the boat was sunk beforehand by the Japanese. The other was in Bataan peninsula and was part of an MG nest not far from a Red Cross tent. He told the LT they should move away from the tent, but the LT told him the Japanese wouldn’t attack something with the Red Cross symbol on it. After the tent was attacked by air, he and his fellow soldiers left for the jungle. I can’t blame them.
But the key reply to your response is this: the day before we firebombed Tokyo, what threat did Japan pose to America or American sovereignty? The answer is *none*. For all the atrocities they committed — and my article in no way excuses those atrocities — by the time we launched our firebombing campaign, they were effectively powerless, helpless before what we did to their civilian population. In “A Torch To The Enemy”, Caidin relates a claim by some in the USAAF at the time that the firebombing raids were less dangerous than using the toilets back at base.
There is no rational justification for the firebombing campaign, not when we *knew* we had them beat, and that the victims were largely women, children, and those unable to fight at the front.