People want to agree with Carol, morally, & I get that, but that's not even the point. The point is, Carol wasn't even right. By the time she killed Karen & David. Others in the camp had long since been exposed to the virus.
We did not see what condition Karen nd David were in when they were killed, but if next week's preview is an indicator, the doctor--after having having coughing symptoms--will have red eyes and more bleeding from the mouth--just like the nerd kid. We all know where that goes, and with no treatment, there is only one path: death and reanimation as a walker. Carol understood what was happening, and there are no hospitals around anymore to jump on an problem before it spreads. As she pointed out, they (Karen and David) would drown on their own blood, so while the healthy are running around trying to maintain things, Karen and David could have turned at any moment.
How long must Rick wait before buying that all important clue? From Amy to Lori, Milton to the nerd kid, the path to death--whether by bite, complications of childbirth, a mortal wound or disease only goes in one direction. If one does not act fast, what happens?
It does not take nearly two years to figure it out.
Andrea certainly did not con herself in the wake of Milton's attack, thinking, "well, maybe i'm just different, and can sweat this out. Keep your fingers crossed!" Carl did not hold back with his own mother. Rick can argue "you did not know," but Carol knew--as well as Rick--that the disease is out of control, and even a run for antibiotics does not guarantee anything, as no one is sure what they're dealing with.
She jumped the gun, killed two people, for nothing & obviously knows that, when she has her frustrated outburst with the water barrels.
We do not know that. She just as easily could be frustrated that they are now dealing with a problem that does not exclusively need a bite or cut from a walker to spread (but will if you give a walker the chance).
Rick's assessment that many won't want her there or will want her executed is correct
Big leap. Take a good look at the decision making process Glorious Rick was willing to make--or carried out: would YOU want to be around a guy who killed his best friend?
For a guy who sees himself as the moral compass of the world, think of his options with Shane: at any time during the second half of season two, he--and others seeing Shane as a threat--could have rendered him unconscious, used two cars to transport him out as far as their gas would take them (for a safe return), and exile him in the same way they were going to dump Randall. Instead, he allowed the problem to continue, but when
HE was threatened--he killed Shane. Yet he justifies it (well, tries to) by saying:
I killed my best friend for you people, for Christ's sake! You saw what he was like. How he pushed me. How he compromised us. How he threatened us.
Nice turnaround. Yeah, he would go on to add Shane's Randall plot in there, but he tops it off with:
His hands are clean for a killing that was all about himself, yet Carol--honestly thinking of the safety of the entire group is the pariah?
That is not maintaining a social order. He's a hypocrite.
Rick is full of crap, and i'm sure his decision will come back to kick him in the ass.