I think higher standards of intellect and weapons discipline would be expected from SF than from your average pongo. Nobody could think that having an serviceable unregistered prohibited handgun and compatible ammunition at your off-base home address for several years is OK. Having the thing kept at the armoury, deactivated or disposed of properly could easily have been achieved.
His release is a populist verdict to satisfy outraged public (whose hearts are in the right place, and support of HM Forces is admirable) but who have been whipped into a frenzy by media who have selectively reported the facts and distorted the issue. There is something fairly ugly about that, and when Facebook campaigns can start to influence the justice system. Most of us know that sometimes good people screw up and sometimes they must be disciplined, and a large proportion of those with first hand military experience thought Sgt N fell into that category. The CM system seemed to deal with him very leniently.
The excuse of 'he's SF so it's fine' didn't work for his mate with a hand grenade in the house, so where do we draw the line? Perhaps the law of the land and that of the forces would be a good start.