When I was in I never recalled running into any dirtballs like that who wouldn't shower.
Because really, if someone did there'd be a protest and the guy hauled off into the shower to clean himself.
Cause there were 45 people in my berthing and we were damned if it was going to smell.
(Was GSM, sitting in an engine room for 4-6 hours a day that at 110+ degrees was horrible, I showered like twice a day on average, most times three.)
But anyways, you've got to take into account the full capacity of a ship fully staffed, what it could run at... Then you think about how many marines they carry, do they support flag staff, extra passengers possible, pilots, hangar crew/flight ops, spacecraft support vehicles and crew... There are a lot that separate from the normal "ship's crew" down to "who runs the ship?" and "who's extra that do other related stuff?"
2,000 total bodies on a Deimos makes sense to me.
A crew of say, 1,400 on average, up to 1,600 standard with the rest being extra bodies, marines for assault purposes or for shipboard defences in case of a raid to capture the ship (I doubt ALL NTF ships were simply 'defected crew'.) Can support a flag staff, so that could be up to 100 or so just to guard and follow and assist a fleet admiral who's there over the captain...
Gah, rambling again...