This was FAR more than just a "personal decision".  As he himself testified, he wanted to open Pandora's box by deserting, and create military chaos all the way up the chain that would bring attention to Afghanistan.  Well, he got his wish.  Bergdahl single handedly caused the change of the entire Afghanistan campaign, with global participants and implications.  He has directly and greatly impacted two US Presidential administrations.  He has impacted international diplomacy and politics.  Even the 5 senior Taliban commanders that Obama traded for him--they went to Qatar.  Qatar is now under a political blockade from the Middle East Gulf State Cooperative nations, why?  Because of claims that Qatar supports terrorism, like harboring these Taliban commanders that Obama sent to Qatar for Bergdahl.  People were injured (and perhaps even killed) because Bergdahl deserted.  This was not just a "mistake" with personal consequences.  Bergdahl royally screwed up on an international scale.