Shane is a bit hair trigger, but it's not the time to be too civil. Hershel is shell shocked, how long was he going to feed his zombie family and anyone else that wandered into the area? How many chickens can you give up to the undead? What next, lead a cow or horse in? Shane got it right, they are not people anymore. There is no cure as far as I can see, and there is no expectation for a cure anytime soon. Anything that crawls after you gnashing it's teeth, while dragging it's rotten rib cage(minus lower body)along, and still wants to eat you, is not going to be cured, and is not civilized.
Rick has the more even temper, but Rick would be missing a son right about now, and if he had to make the call would he have told Shane to stay and be eaten, giving his son no chance? If Rick went back for supplies, would his son and himself both be eaten?
A leader probably has to fall somewhere between the, lay down and drink the kool aid, and running naked through the forest with an AK47. Herhsels's way of life post Zombie apocalypse, is not wise, and could not be sustained long term. Pretty soon the living are going to want those chickens.
It was fitting that Rick shot Sophia, Shane did not have to do the dirty deed for once. Sophia being the the barn was a good thing, it showed the group that nobody is exempt from a piece of lead once infected. There was loss on both sides, Hershel in the end, allowed the barn's herd to be put down, he never tried to fight it, there was no winning this one.
Somewhere in their future, there would he an actual safe long term place for them to live,they can then return to the land of rules, and lines you should not cross etc. Right now it's still the law of the jungle.
"Now this is the Law of the Jungle—as old and as true as the sky; and the wolf that shall keep it must prosper, but the wolf that shall break it must die.
And as the creeper that girdles the tree-trunk, the Law runneth forward and back;
For the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack."
PS I agree, now we have to wait for more brains....