I was also in the "zombie parts wouldn't kill you" camp, but just read this from the amc website:
While scouting the prison tombs, Hershel is bitten in the leg by a walker and Rick amputates to prevent the infection from spreading.
So a zombie bite yields a lethal infection.So now the question, if Bob was scratched/bitten, why didn't he chop his own leg off as soon as they got back to base? With that, I'm leaning towards DS's theory, recovering alcoholic going outside to deal.
Maybe Herschel never told him how he lost his leg?
Have to think the ole "what to do if bitten" topic of conversation has come up around the campfire a time or two. Even if Herschel didn't personally tell him, you have to think someone did.
That's one of my issues with the writing. The reality is that this zombie virus would still remain a major and ever present antagonist in the survivor's world. But how little is there in terms of evidence that it is still in the forefront of the survivor's minds? There is a certain sense of "normal" in having to face walkers everyday for the last 18 months and people adapt to life altering changes in their existence, but that doesn't mean that the sense of worry about this mysterious infection has evaporated. So you'd think that when you meet new people, after you decide not to kill each other, you'd start sharing notes about both the virus and the walkers. How does it spread? How do you avoid walkers? What is required to kill them? Are there ways to trick them or tame them? Has anyone ever communicated with one? These are conversations that absolutely would be happening. And since not everyone had a sit-down with a CDC agent, you'd think Rick's group would have some pretty critical information to hand out and would once they thought you could be trusted.
So while I understand that a lot happens off camera, I also think there's opportunity there to still use the virus and survivalism in a plot advancing way. And while they are using Big Red and The Mullet as the "find a cure" guys, it's like they are using that to create more contrived drama between the characters instead of just letting the virus and basic survival itself still be part of the story.
I mean, why wouldn't everyone go to DC? What other plans do they have? How has trying to find a static, safe fortress worked out for the group so far? But here's the big ever present issues: food, water, shelter and safety. At some point the canned goods run out. So what are they going to do for food? Farming is the obvious answer. But that makes you not only static but also puts you out in the open. It's a multi-month commitment. And you can't raise corn in Washington D.C. in the winter. And how to do warm yourself in the north over a winter without making yourself a target for walkers and looters? And what happens to walkers in freezing temperatures?
So there is this huge potential to use the wander vs. stay argument, as defined in very rational and realistic survivalist terms, as a point of disagreement which then can create drama. But instead the writers have Carol wanting to wander off lone wolf style because of some introspective, frivolous and unrealistic psychological turmoil to be conveniently present when a mystery car drives past so that she and Darryl get separated from the group so that there will be drama and suspense over whether or not to leave now that Big Red has waxed eloquent during a toast and all of sudden convinces everyone else to move out.