Yeah and not a one of them has figured out that a silenced 22 makes a whole lot more sense than a 44 magnum or crossbow.
It goes beyond that. What about armor or shields? It seems to me that they could encase themselves in armor from head to toe. Given that the opposition's weapons are limited to hands and teeth, heavily padded clothing would constitute effective body armor. Instead of knives, they should have spears or swords. For a serious number of humans to succumb to the zombies, they need to be candidates for the short bus. It's pretty obvious that the humans on the show have also been infected, but with a virus that makes them stupid.