This is inane. If the canon says Earth is red or the Orion is the biggest ship in the game, it's WRONG. Of course, in this case we have only speculation and I have no problem with accepting the number. Simply saying 'lolz canon is teh rightzor allah time' is bollocks.
Irrelevant. While you seem to think a corvette staffed by 6000 is as outlandish as 'The Earth is Red' or some such crap, go right ahead. But we're not talking about something that is contradicted by ingame event or common fact. Hell,
it's not even contradicted at all! Why you compare it to easily contradicted facts i'll never know, but doing so is and forever shall be completely irrelevant to the discussion.
Really, I think the issue is size and not capability. Corvettes are nearly destroyers-without-fighterbays, but are much, much smaller. 4,000 extra guys isn't too strange for the destroyer fighterwing, but it seems wrong to us because an Orion is many times larger than a corvette. The Sobek is pretty damn small, but without contrary evidence we can't really just ignore it. Unless someone wants to scale it and reveal it would be physically impossible to fit 6000 men in there or something.
If you seem so sure of yourself, get 6000 scale-model Vasudans and whack 'em into the Sobek to see if they fit. Go on, do it. I think you'll be unpleasantly surprised.
On a side note, are we told how many Vasudans are present in a Hatshepsut? I only ask as it seems rather off to compare a 10,000-strong Orion compliment, a completely Terran vessel, to a completely Vasudan vessel that may be constructed in an utterly different manner. I mean, we've seen Shivan architecture to be decidedly alien, so is it such a stretch to assume that Vasudan architecture may be sufficiently different from Terran architecture as we know it that it could explain what
some would deem a ludicrous compliment figure?