It's the whole "this person risked their life for us and should be treated as such" Besides, it's Semper Fi, always faithful, to god, country, fellow soldier. Most likely the threats are coming from other Marines.
Does he deserve to go to jail? Yes, it's a theft crime, grand larceny to be exact. Is it better if he stays out of jail? Yes, he can work to repay his debt. Should he resign as Mayor? Personally I don't want a mayor that is a thief. Should he have his *** kicked for stealing from someone in grief? I would be glad to.