By and large I agree with you. No child deserves that, whatever it's colour or creed. But they were different times. You couldn't fight the Nazis by playing fair and you certainly couldn't fight the Japanese by playing fair.
The Japanese were a warrior nation, they despised weakness, which is why they treated our POW's so poorly. In their eyes anyone who surrendered was less than a man, that's why they didn't treat them like men. You can't fight a nation with a mindset like that by playing fair and you can't judge the people who had to fight them by todays standards.
The Japanese got off lightly, very lightly for the atrocities they carried out for the sake of conquest and expansionism.
We were defending ourselves, they were hell bent on conquest. You can't start complaining if you kick a dog and it bites you.