The thing that I remember and picked up on in great detail was the overwhelming despair the Syrians went through every day. Whether it was the constant bombings, fear of death, public executions, or even being forced to flee under methods that were not safe. The faces of the kids who were either constantly crying or cowering in fear with their parents was alarming and created this feeling of sorrow that they have to face this. The reason to leave in this case is purely for survival and avoid death.
So, when it comes to Josie and her decision to leave it is a rather small, irrelevant one. If I were to identify her reason for leaving it would be similar to a mid-life crisis rather than a necessary reason to vanish with her kids. Although she did have valid reasons to move such as the death/guilt of Jeremy, losing her job and dental office, or being alone those can be fixed and are temporary because they take time to resolve but once they are they are no longer issues.
While contrasting the two, both Josie and the Syrians have a valid reason for themselves to leave and find a better place to live or start anew. However, in terms of importance to leave it has to be with the Syrians because at the end of the day, Josie, still can return home in Ohio or continue to travel where ever she wants but the Syrians cannot return in any way what so ever because of ISIS or may not want to return at all.