I can't tell if you mean there's no indication of player choice or player character choice.
Regarding player choice, you're correct. That's why a lot of poeple so far have said "your players need to be okay with this setting". I personally thought this was obvious, since it's GMing 101, but just in case it's not obvious, I agree with everyone who has pointed out that when you have any kind of hard restrictions on a campaing setting, the players need to be told ahead of time what's up to make sure they are okay with it.
Regarding character choice... I don't have a very enlightening comment. You're also right there, but it's opinion. The PCs simply don't have a choice here; it's baked into the initial state of the campaign. There are a lot of things I could say about that. In life, we often don't have choices about certain aspects of our destiny. That's one of the appeals of playing a fantasy game; to face the challenges of dramatic stakes to a gratuitously high level that would be unfathomable in real life (like having to defend onseself against terrifying monsters, for example). In this case the theme is "your previous life was stripped from you, and now you only have a sliver of opportunity; what will you do with it?" Like any RPG, they actually do have a choice during the meaningful part of play, which is everything they do after they've taken the oath. But the oath-taking is a part of charcter creation. All newly created character have taken the oath. It's no different than running an RPG where every character is a detective. You might not like that there is no alternative choice for your PC - you must be a detective - but then why did you sign up for the detective Campaign? What it ultimately boils down to is that when I advertise this Campaign, people who find this theme distasteful will not wish to play and that's fine.
Edit: I had another thought after I posted this. If the reason this lack of character choice is an ick-factor for you, it could be that the part you enjoy about RPGS is when some of them give you a blank slate to make your character with, and they don't require you to have specific major parts of your character be predetermined. If that's a hangup for you, then this clearly would not be the kind of campaign you'd be interested in. I'm only going to be looking for players who don't require that level of freedom during character creation. Another example: stats and character traits will be rolled randomly. Some people really don't like that either, but that's the system I'm running.
your additional thought is not applicable to me; you're trying to read way more in than I put forward, and in so doing, getting it dead wrong.
I have no issue with constrained character gen. I don't really care for blank-slate, either; my favorites have lifepath generation. I simply strongly dislike slavery as a key element of the setting. Which it is, and which it appeared you were obfuscating in your description.
There is little reason for such conscripts to return from an away mission, either. which implies even more control subtext that isn't described. And if no such control is in place, then players might decide to simply escape.
On the other hand, there is the issue that, given the combination of being kidnapped and forced into servitude, if players are good with that, I, as a player, would likely not want to game with that crowd ever again.
And I say this as someone who's run a number of games with serious ick-factors... but always with PC's fighting the ick-factor, not being the
ongoing victims of it. That is also why I've not run a game of Revised Recon yet; 60% of soldiers were there because of the draft - either selecting to join before being randomly drafted in order to secure non-infantry arms MOSs or because they're being drafted. It's also what holds me from suggesting MASHed. Meanwhile, I've run active military campaigns in Traveller, Trek¹, Star Wars², The Babylon Project, and Mechwarrior.
Notes:
1: Including unlicensed but clearly knock-off games, most notably Starships and Spacemen, and Battlestations!
2: Rebel Alliance only, never imperial.
