Men as stubborn as him don't see anything else. It was a necessary change. The walkers busting out of the barn and attacking everybody was inevitable. Made only more dangerous by an old fool who doesn't see them as such.
It was Hershall's moment of clarity. His hopes of a cure were blatantly and ignorantly endangering himself and his family, and getting her back were delusional unless he was gonna tie her up and resort to necrophilia until she completely decomped. I'd also like to point out that while he thought they were salvageable, with Otis doing the wrangling and the blonde doing the feeding, he sure as ____ "conveniently" made certain he didn't go anywhere near them.
Are we watching the same show? Shane shot up the zombies in the barn thinking Hershall was home. He didn't know he'd run off with Rick who was brown-nosing so his wife gets the proper prenatal care. Rick knew the walkers were dangerous and despite that, could only think of himself, his wife, and the unborn child. Not saying that's wrong, but it's hardly "thinking for the group."
[insert equally low blow about poor taste in women]
Blah-blah-blah. It doesn't change the fact that without it, Carl would be dead. Without Otis' sacrifice, Carl would be dead. Without Shane doing what he did (agree with his methods or don't), Carl would be dead. Shane had a sprained ankle and Otis, with or without the packs, was putting them both in danger. It's a shame Otis couldn't have been honorable and thought of the people he'd ____ed over by shooting a kid and sacrificed himself. Fortunately, Shane saw the bigger picture and had the balls to do what he did.
Besides, there's only one person in the group whose direct actions got a child killed. Newsflash... It wasn't Shane.