active role =/= singularly and personally responsible

it's reductive to place the blame on one human

Japanese military decision making, counterintuitively, became more and more decentralized during the second Sino-Japanese war. Commanders like Masanobu nucleated the idea of "gekokujo" "leading from the bottom" which essentially balked at orders from the top thought "not honorable enough". This concept and it's proponents are largely credited with the brutal invasion of Korea, Manchuria and China.

Hirohito certainly wasn't asking them to shishkebab babies or even asking them to stop because that simply was not his job or anything to worry his dainty little head of state over