Why are they compared to each other? Completely different people operating completely different systems with completely different goals.
Hell, even in solely the former case it makes a large difference depending on the specifics of the intended target of direct purposeful harm.
More generally, intent is a huge factors in evaluating responsibility & level of harm, and to a lower level so is specificity.
Western society in general has plenty who want to try these policies again because they say this time it will be different.
Hitler and Stalin resided in the same town for a while http://www.bbc.com/news/magazine-21859771