Well if droids are slaves, so is just about every other sentient robot or android character that's ever appeared in SF movies and tv. Data is the rare exception.
Luke's somewhat different attitude toward his robot friends may have been shaped by working on the farm and being more "hands on" with them than even his uncle. Yet, he still sends them on dangerous errands.
One of my favorite story arcs in the old Marvel books was that of Valance the bounty hunter. He had a unique hatred of droids, (and relished blasting them to bits) but eventually had a change of heart, thanks to a certain protocol droid.