I disagree. Looting and plunder have been time honored traditions. We only have waged war 'civilly' in the last hundred years or so with professional soldiers fighting other professional soldiers and obstensibly leaving the civilian population alone. Without a native civilian population to garrison, resource grabs become much more simple, you know? And we have, as a nation, amply demonstrated our failure at garrisonning and controlling the native population in multiple world conflicts. Imagine how much of a disadvantage the rest of the world would be at with restricted access to food/water/oil? But other people might not think too kindly of screwing with their livelihoods. When a coalition of force opposes our armies, then its time to get out of dodge.