If someone was trying to kill you, would you kill them first? Even pre-emptively? If not, you would not survive. And you would not deserve to.
There have been several people I’ve run across over the years that I would like to have “Pre-emptively” killed. But something told me it would probably not be a good idea.
The last few episodes have kinda focused on that particular moral question haven’t they?
Your encounters in the past have been questions of morality. The question before Rick and Co. is survival. There is no time or place for finely tuned moral conundra. That comes when the basics are covered and you have the luxury of reflection.
The answer to the question "What have we become?" is "Whatever we needed to become to survive." When we no longer need to be that, we can revert to a more civilized state.
It's not complicated.