This is the part where it hits the ick factor for me: There's no indication of choice. The PC's seem to be conscripts with a forced oath. In other words, draftees. Slaves of the state. ("Slaves of the state" has been used in some anti-prison-labor arguments, as well as anti-selective service rhetoric, for decades.)
If you're "rescued" into servitude, you're not rescued, you're kidnapped.
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.