I don't quite see how this relates to the points I made about work permits.
Not a fan of the 3rd party ownership at all, but I think there are situations a lot closer to slavery outside football.
Clubs (and unfortunately 3rd party owners) give these kids a chance to make it as professional footballers, when they don't make it quite a few of them are left with nothing. This is unfortunate, but no different to what would have happened had they not been given that chance. I have no more sympathy for them than for some other kid from some third world nation that had even less footballing talent and is left with nothing.
From a broader perspective it's somewhat relevant. Clubs and agents are taking advantage of these young kids in the hope of making money. Why not fund more academies in their home countries? Instead they're stowed away at some small club in Belgium, then kicked out two or three years later, with no money and nowhere to go to, if they're not good enough.
There's a natural chain of progression for most players (unless they're super talented) that channels money down through the leagues. With the already mega rich clubs trying to bypass this to line their own and the agent's pockets they are killing the small clubs.