Well i highly doubt the walking dead are neutral for the environment, what will happen for them, when there are no more humans? Will they just live in harmony? I highly doubt it.
From nature's perspective I still think the progress of mankind is a much better longterm solution, because yeh mankind will 99% of the time have war at the start, but will become ever more peaceful with technology.
But I guess I took this very far out on a tangent lol.