They wouldn't have had to defend with a scorched-earth policy if Napoleon hadn't invaded, would they? Or they could have surrendered and start serving some relative of Napoleon as ruler while he sacked the place, because that was the kind of peace treaty Napoleon went for. I don't blame them for resisting in the best possible, and as it turned out effective, way. I do blame Napoleon for all his wars. The french also absolutely wrecked the Iberian Peninsula, razing entire cities for resisting. Would you say that their victims were to blame for having resisted the invaders? As a warmonger, Napoleon was worse that a Hitler of the 19th century: he had opportunities for peace, had peace treaties done, and constantly went about breaking the treaties and starting new wars, because he was utterly unable to scale down his imperial ambitions. And as a destructive force in Europe he came near. The french "republic" like to talk the nice talk (human rights, yeah...) but their actions were the opposite even before Napoleon.