they're not smart at all. every safe place they've got involved with has gone to ****. the farm, the prison, woodbury, the cannibal place and now this place.
the smart people are the people who create the havens. rik and his group come in, think they're better because they've been dumb enough to never form a long term base and have to rough it in the wilderness and thus pick up a few basic skills in killing.
the preacher is right. they are the devil in disguise and have left a trail of death and destruction in their path.
I agree with some of what you are saying however I don't really see it as Ricks groups fault.
The Farm: It was remote and they were safe until a random horde strolled through. Lesson learnt, get bigger fences.
The prison: bigger fences, only fell as a lunatic drove a tank through them.
Cannibal place: Well how could they have seen that one coming?
They did what they had to to survive, that's the point of the show really.