But they werent conducting an evil war. The things being referred to as evil werent known at the time for their part and the US admitted that we didnt actually know about these things occurring. The US refused to let a boatload dock and sent them away because the US didnt want them either.
None of these things were understood to be real let alone “evil” until the end of the war.
Oh I think they know in 1944 and 1945…. But decided the best way forward was to win and end the war. There’s a whole ‘nother discussion there.