In the Lucas movies, droids are pretty explicitly portrayed as chattel slaves. They are auctioned off, have separate inferior quarters (Jabba's droid quarters are particularly notable), and are basically treated as beings without agency despite definitely having agency. There's even an explicit visual analogy - Anakin and Shmi have collars that control them and could kill them, and the droids also have (spaceships shaped like) collars that control them and can kill them.