[DenisM]

Well, "the crime against peace" is a single-serving "let's stick something on them" charge. US engaged in multiple aggressive conquests after WW2 without anyone even mentioning the word "crime" in a serious context. So aggressive conquest is a common practice, whereas civilian massacre is universally frowned upon - a big difference in my mind.

I can see how to tie holocaust to WW2 - the regime which perpetrated the former has then also started the latter. Stalin didn't launch the WW2, but then you can argue he did set it in motion with the Ribbentrop-Molotov pact making both the purges and the WW2 part of his empire-building. Good point, I agree.