[quote=@tobiax]
[@tanderbolt] Winter isn't a Hunter because she's a special operative. And he didn't abandon his post,he stayed there.
[/quote]

As his backstory is written, he did eventually leave his post after meeting the scavengers, and without being ordered to retreat he technically has forsaken his duty. Even if the military would forgive him, he has enough bitterness to not want to go back to Atlas.