Little has changed since the 1930's and 1940's.
Some Things Never Change
If Adolf Hitler had not been an imperialist who sought global conquest and domination, and assuming everything else had remained the same, would the world have allowed him to purge Germany of its undesirable citizens provided the slaughter had stayed a strictly internal affair? The answer is, probably, given the prevailing laissez faire, isolationistic foreign policies of the 1930’s and 1940’s.
In like fashion, had Saddam Hussein not been an imperialist who sought to invade neighboring countries, and assuming everything else had remained the same, would the world have allowed him to purge Iraq of its undesirable citizens, and do so with impunity, provided the mass murders had continued solely as an internal affair?
Some might suggest that societal, ethical standards have not changed much, indeed little, since the 1930’s and 1940’s. And I would tend to agree.