Oh, come on. If he has zero troops there's no way he's attacking into three offensive wars for the sole purpose of losing infrastructure.
I think turtling is remarkably similar to what happens in real life. There are no troops, so no battle is fought. Hence, less damage is done. Fortunately, every leader in CN follows some version of the Geneva Convention, so your troops don't just go off destroying stuff willy-nilly when it's all civilian anyway.