"Commit less atrocities" in this case is just code for permitting others to commit whatever atrocities they want. American "atrocities" against Japan pale I comparison to what the Japanese were inflicting on the rest of Asia.
It's not a code. It's literally saying leave doing bad things to bad guys. Instead just becoming one of them but being proud about it because your atrocities were somehow better because the cause justifies the means and your cause is just. By that logic jihad is fine.
Have you noticed how in history good guys always eventually won every major conflict? What are the odds? 100% if you paint a bullseye after you shot.