Candide's Punishment

Candide's Punishment:
Well, there are lots of punishments Candide has to go through.  The first of which was being kicked out of the Baron's house for kissing Cunégonde.  I can't say I agree with this, but Candide broke the Baron's rules and was kicked out.  And so started our story. 
The punishment that I would like to talk about is the one he received when he deserted the army.  He was given the option of death or beating.  The beating was severe though it would have eventually resulted in death, therefore Candide was given two options, each of which were "equal worse".  Do I agree with death for desertion?  No. 
It has been a common tradition that people who desert are killed or at least severely punished.  They did not uphold the honor of their country, are utter cowards and deserve to die.  But why should war be any different from other professions?  We don't kill people who desert the medical or law professions.  We don't discipline people who leave whatever occupation they hold when they change their mind.  Why then should we have the right to kill those who leave one of the more stressful and dangerous professions in the world, that of a soldier? 
I know nowadays we have stopped killing deserters.  But it is still dishonorable and results in discipline.  Is this practice right?  I know giving up is looked down upon, but people should be given a fair chance to leave when the going gets hard without repercussions.