Though even in that light it's difficult to understand why people like Ishii weren't quietly hanged. I can't imagine his cooperation produced a nontrivial amount of useful information we couldn't have gleaned from documentation.
But I suspect the reason was they viewed Naziism as a greater evil than Communism, whereas the emperor worship in Japan was seen as relatively harmless. Though they did hang a whole lot of Japanese politicians and officers.
They wouldn't. CIA was also doing human experiments yet, although we live in a democracy, nobody held them accountable. You see, as long as a government cannot be held accountable by its own people, all bets are off.
CIA controls all western media, so good luck "making people aware".