Many countries around the world can choose to invest in agriculture or weapons, and they choose weapons. I don’t like the food grown for fuel idea, but a lot of the blame should not fall on us.
The problem is, you get the weapons in order to acquire the food (i.e., land, water). Hunger—>war just as much as war—>hunger. I daresay that most countries on earth can’t feed themselves. We could, but we’d have to skip the kiwi fruit.