At some point you have to look in the mirror though. That’s a big part of what happened this season. Alexandria gave them a chance to rest, and reflect. And during that reflection a lot of them thought “damn I’ve killed a lot of people, and I’m not 100% convinced every single kill was necessary”. That’s where the doubts came in, because if you’re going to build a society you don’t want it’s foundation to be moral rot. Remember when the prison was stable and they developed the 3 questions:
how many zombies have you killed
how many people have you killed
why
They started asking themselves why, because good people do that. And they started not liking the answers. Except for Rick, Rick’s gotten a little severe, volunteering to take out Negan with ZERO information (didn’t know where they were, who they were, how strong they were, why they were doing these things, IF they’d actually done these things). Which is part of this build up, at this point there’s no functional difference between Rick and Negan, they’ve both decided they’re strength is killing and they’re both willing to kill to get half your stuff.
And yeah, you kind of have to agonize over it every episode. Because that’s what morally healthy people forced to kill do. They don’t like it, it bothers them.
Part of what you’re missing is what he show is actually about. The show was NEVER about zombies. It was always about people. What do people do to survive this situation, and how does it affect them, and then how do they deal with those repercussion, and how does THAT affect them, etc etc. The comic, and the show, is about repercussions. And yes, there will always be somebody, because out here in reality there IS always somebody, but how you DEAL with that somebody declares who you are as a society and what your situation is. We didn’t deal with the British the same way in 1812 we did in 1776, because we’d changed as a society. WWII was fought differently than WWI, change. There’s 4 distinctive eras to Viet Nam because we were a different people.
PROBABLE SPOILERS (because who knows how closely they’ll follow the books)
In the comics Negan is a serious game changer, because they’re in a different world. In Alexandria our survivors have the largest society they’ve had since the outbreak, with the largest number of serious non-combatants they’ve ever had. This makes them need to deal with Negan differently. Plus they have allies in Hilltop. And a 3rd set of allies we just barely met in the TV show called The Kingdom. But of course they have the lessons learned from dealing with the Governor, they know half measures don’t work. But they also have more people to protect than ever before. And they have allies.
In the books they don’t kill Negan. They take him prisoner. Rick decides that to proceed on the path to civilization they need to get away from all crimes being punished by execution, eventually all societies figure out non-permanent punishment. Also I think Rick realizes just how close to being Negan he came, and that Negan’s pretty smart, so he wants to keep him around both as a reminder and as a confidant. The war with Negan included a multi-year (real world issues shipped year, not internal to the story) stretch with no zombies killing anybody, which only ended because Rick’s strategy for defeating Negan included herding zombies to overrun a couple of Negan’s positions.
Then they have a period of peace. They by and large settle the land between the 4 places (they “resettle” the Saviors area), they even start having commerce by boat with other places. Then a new and really twisted enemy shows up. And now (like really now, a couple issues ago) Rick has realized that while they are by and large at peace, there’s always somebody (because, there’s always somebody, remember when we thought the end of the Cold War meant we had no more enemies) and while this mild patrol thing might work sometimes over the long haul they still need a fighting force, a dedicated fighting force. So now they’re mustering up a standing military.
END PROBABLE SPOILERS
It’s an evolving story. But it’s about people. Not zombies. Zombies are just the stressor that caused the first couple of decision, and after that they’re just background situation. Like putting the story in the desert, or on the moon.
Second, the Rickites -- and all the other survivors -- need to stop sitting on their hands waiting for the zombies. They need to mount a systematic offensive against them and eliminate them completely. Set a goal of 1,000 a day and slowly clean the planet of them.
Third, start making your settlement self-sufficient, so that instead of having to scrounge for leftover supplies, you can build, create, or grow your own.
Then, once you have your own needs met, start putting out feelers for other settlements who might want to trade. If they seem aggressive, infiltrate, recon them, and if they can't be trusted, make plans to wipe them out. Or at least anticipate that they are planning the same fate for you.
But I for one do not want to watch episode after episode of Morgan yammering his Taoist blather or Carol sniveling because she can no longer kill to protect the people she loves.
The Rickites keep getting surprised by these predators because they're careless. They should know every blade of grass and every breathing human being within a hundred miles of their settlement. If they're friendlies, they should be invited in and incorporated into the group. If they're hostiles, they should be destroyed when it's safest to do so.