PS, before anyone thinks that I'm accusing The Walking Dead
of the same obnoxious sledgehammer moralizing that nuBSG
was guilty of, rest assured I'm not!
The "moral analogy," if it exists, is entirely being left in the minds of the viewers, which is where such things belong. What we've seen on screen could be intended as nothing more than a psychological exploration of the stresses that people are put under, in extreme circumstances. It's up to the audience to decide what to make of it all.