Deliberate killing, versus callous indifference to deaths caused by your own policies, versus incompetent incomprehension that you are causing such suffering is certainly worth considering.
But I do think you have a greatly overinflated idea of the numbers who died as a direct and a long-term result of the atomic bombings. Direct victims were fewer than some of the conventional bombing raids on Japan. And although many suffered, the numbers who died of radiation-induced diseases was surprisingly low. The British killed, or perhaps more charitably failed to save, vastly greater numbers in both the Irish famine and the Bengal famine both of which they handled inexcusably badly. But that pales before the numbers Mao and Stalin wiped out with their ideological reorganisations of farming which could not be questioned.