My thought about the whole thing is when ever the main group runs into another group they will do what ever it takes to protect the group and stick together.
They will screw over every other group to save each other.
If groups like the farm group won't allow Ricks group to stay or do what "they think is best" the farm group will be destroyed and so on down the line.
They will absorb people that don't have anyone else or people agree with them, and they will be the fodder.
i also have not read the novels at all