Well, what he's saying is true, I guess. Genocide also brings peace. As does nuclear war. Don't mean they're good things. And as Xahar pointed out, it took western Europe over a millennium before they got war "out of their system". Are we to let third world countries kill each for a thousand years while we sit idly by? I think that, as we have the means to do so, we should do what we can to alleviate some small amount of death and suffering in the world, as long as we are able to do so in a successful manner (i.e. not Iraq). Obviously this doesn't mean Wilsonian/Bushian nation-building or whatever, but it doesn't mean that we should ignore genocides and wars that we can prevent.
I agree with what Lief is saying. If your neighbour's house is on fire, you don't pull up a deck chair and watch, you don't suggest that it's a good thing for your neighbour because 'once it's burnt down, it won't burn no more,' you lend a hand, you call the fire brigade. We are all members of a global community and we have a responsibility to one another as civilised nations and we owe a duty of care to those who are less fortunate: the poor, the hungry and the defenceless. Human history is littered with the examples of our inhumanity towards one another. When we see genocide taking place, it shouldn't matter whether it is occurring in Germany or in Rwanda - it is wrong and it should be stopped.
