Here is my thought on the whole Rick/Sasha being lost idea.
Sasha, is bat shit crazy, I will give you that one. Rick however, his whole reason for living is to protect his group. I feel like he would risk his life for any of them. Sasha acts like she wants nothing to do with anyone, whether it be the group or working on establishing a way of life. She is exiling herself. Rick wants to ensure this place survives and is working toward that goal. Rick is certainly brash and the evil they experienced in the world has certainly warped his perception, but at the end of the day his goal remains the same. I even feel like his methods of ensuring Alexandria survives are better than Deanna's. She let's a known abuser continue to live with his wife and kids, where everyone knows what he is doing to her and turning a blind eye. That is the type of crap that goes on now, and it sets our civilization backwards. Rick wants to do something about it, and he becomes the bad guy? If I were a member of that community I would have sided with Rick that something needs to be done. However, taking him out back and shooting him, as Rick suggests is a little extreme. Deanna claims she wants to create replicate an established government and get the world back as normal as possible. But tells Rick "What do you want me to do?" when he asks for for answers about Pete. Do something. Then she doesn't come up with any method of dealing with rule breakers except exiling them? That's pretty stupid. Rick has also said countless times that these people have no idea what they are doing, and they clearly don't. Aiden's scavenging team and the construction team as examples. They would have let that woman die if it wasn't for Abraham and who knows how many people died due to Aiden's stupidity and would have continued to die under his watch. Plus the people of Alexandria right now are nothing but selfish. Nicholas is directly responsible for Noah dying and wants to leave Aiden and lies about it. They are not loyal to one another. They should learn from the bonds that Rick's group has. If anything the people of Alexandria are too soft and not hardened enough to survive out in the real world. As much as Deanna wants to replicate life before the outbreak within the walls, it isn't living in the real world. If you ignore the outside world, you are just asking for external sources to come and ruin what was established. Rick is simply trying to stop that from happening.
Look at the last person who they didn't kill given the opportunity (Michonne & The Governer fight or Andrea who could have stabbed him while he was sleeping or Rick who could have killed him during their little meeting). He came back and killed so many more. So I certainly understand Rick's thought process. If you cut the head off of a snake, it dies. If you throw the snake out into the wild it can come back bigger and more dangerous.