That there are only two options in life, kill everyone, or run away like a [censored].
Anyone else find it amusing that they left the fate of the Valley up to some random courier who wanders in with a caravan, he's been there like a day and he gets to decide the outcome of an entire tribe of people, against the wishes of someone(Joshua or Daniel) who basically leads them. lolwut?
I do find amusing how can someone reach that conclusion.
With the exception of the LAST quest the entire quest line is based on Daniel plan of evacuating the Sorrows, when you get the map to the Great Stairway you can continue with Daniel plan or side with Joshua Graham idea of taking the fight to the White Legs.
The only thing that is "amiss" is there is not much of a buildup to fighting the White Legs but its pretty clear Daniel have not much of a pull with the Dead Horses and without Graham help he simply cannot start the evacuation of the Sorrows, your decision simply can tip the balance as Daniel NEEDS Joshua and the Dead Horses help but Joshua does not need Daniel help.
The real question is why Joshua Graham did not go ahead with his plan even without the Courier support since he really did not need the Courier help unlike Daniel that had not much of a choice since the Sorrows refused to entered the caves and the buildings and so did most of the Dead Horses, that is the only weak link on the story.