Dave Eggers said this quote
“ Max had to think about these new developments. He hadn't liked getting hit by a rock--his stomach still ached from then rock Judith had thrown--but then again, when his team had used rocks on Alexander, it had caused him to surrender. Now the Bad Guys only had three soldiers left, which would make victory for Max's team more likely. So now it made perfect sense. He was wrong to ban rocks, or even animals. The key was to use all the weapons at one's disposal, but to just make sure you won when you used them. ”