[Legbreaker]

Nobody is saying they're ALL getting demobilised. Those who want to go are likely to be recognised as probable deserters after a relatively short period (possibly after the first thousand disappear over the nearest hill) and demobilisation on a voluntary basis instituted in an effort to prevent those people taking valuable military resources (ie weapons) with them.
Also, as has been pointed out, we're not actually talking about 43,000 military personnel here. 6,000 went to the middle east. Another substantial portion are civilians (lets call it 10% or 4,300), and then there's the permanently disabled from wounds, illness or radiation poisoning, say another 10% (which I judge very low given the length of the war and lack of evacuations and reinforcements).
This leaves us with just 28,400 military personnel.
Now lets take out those shipped to ports other than Norfolk. Shall we say another 10%?
Now we've got 24,100.
How about naval and air force personnel with little use on land, such as cooks, clerks, missile techs (like they're going to be needed post war on more than a reserve basis), navigators, helmsmen, airframe fitters and so forth. At most they'd be assigned a reserve status, subject to recall in the unlikely event they're needed again. I know, lets call that group a conservative 10%
So we're down to 19,800 useful troops.
Of that number, there's going to be some who head for the hills at the first opportunity, taking anything and everything that's not nailed down. Might only be a handful immediately, but as fears of a food shortage kick in around day 3, that trickle will likely turn to a flood.
Voluntary demobilisation, as previously stated, at least puts some sort of a control on what is walking out the door. Perhaps the sweetener is NOT facing a potential firing squad for desertion, AND Milgov provides a parting gift of a couple of weeks food and basic supplies.

Yes, troops could be retrained to cover needed skillsets, but that takes time. Time, which we all know, Milgov doesn't have. Reducing the military's food and support requirements are critical concerns and must be attended to if they have any hope of retaining control of even a cadre of useful personnel.