As Woider touched upon and Savin told us not to think about, where the balance of power is really obviously skewed the excuse 'But they agreed to it!' doesn't hold water at all. See: pretty much any example of current day exploitation.
I agree with Savin's implicit train of thought, though: The U.G.C. is presented as a deregulated, hyper-capitalist society over which corporations have huge sway, and as such stuff like the commodifying of convicts is a natural consequence. It's naive, unrealistic and borderline negligent to show nothing but the upside of being able to buy and become whatever you want, as long as you or your daddy have the creds. And he's actually gone to lengths to make the situation at Gastigoth less terrible than he could have, so he's taken something from the various NT debacles at least.
None of this would matter of course if it wasn't for the fact really sleazy shit like this is hot as fuck. Sensitive souls such as Misty disagree of course, but I'm constantly being informed that the Beth's Broads bad end is one of the hottest things in the game, despite the fact I put relatively little effort into it. Power imbalances really hit those deep, red places in the human brain, fortunately for us smut writers and unfortunately for the species as a whole.