Slavery can be a sensitive topic in the context of a roleplaying game. Enslaving entire races or species is heading even further down the garden path. One way to treat it is to have your band of heroes fight against the slave traders. This does pose the risk of having them perform morally upstanding actions though. Easier to just let them kill monsters and loot treasure, really.
Oddly enough nobody ever seems to have a problem with that.
Nute Gunray: Naboo is but one stepping stone on the path to plogress.
Nute Gunray: Meanwhile my sreeper agents bide their time.
General Grievous: Pray tell.
Nute Gunray: The Rost Orb of Phanastacoria is not such an innocent trinket as the Gungans think.
Nute Gunray: Soon, thanks to that fool Dookû, the Trade Fedelation will have a conduit worthy of its grory.
Nute Gunray: And you will have the power you clave.
General Grievous: Sterling! Enslaved races shall volunteer their brains for my exquisite cyborgs!
Nute Gunray: Cyborgs will not be enough. Losing the crone troopers was our gleatest setback and, unress we are careful and swift, may prove our downfall.
General Grievous: Careful?! Care is for swaddling babes and razor blades!
Nute Gunray: Enough. This meeting is over. Go to Naboo and oversee the conversion plocess.
Obi-Wan: Well I'd better capture him before he leaves or I might have to go to Naboo.
GM: Oh, now you're just being contrary.