I don't know if I back the argument, but I'd suggest that widespread knowledge of a class of people being wiped out greatly increase the stress, fear and terror

I don't know if I back the argument, but I'd suggest that widespread knowledge of a class of people being wiped out greatly increase the stress, fear and terror struck into the hearts of all others in that class who have yet to get rounded up. furthermore, if they flee, communities get uprooted. and, though I hate to say it, whilst the killing of a man is in some cases justifiable (self defence, death penalty if you're into that kind of thing, which many societies worldwide are, etc) i really cannot see any argument for systematic killing merely based on race.