If you were to remove PVP within 2-10 blocks of spawn, then humans would just camp at spawn to survive. Are you suggesting that we remove PVP for humans within 2-10 blocks of spawn? If so, good idea.
If humans want to spawn kill, let them spawn kill. It makes it easier for zombies to find the humans and it doesn`t take long to get to them. And what is the difference between all the donors at spawn getting rofls, and all the donors at another spot getting rofls? They will still be killing zombies, zombies will still have a hard time.