By synthetic humans I mean fully functioning human androids/and-or clones from ourselves. And the main purpose of their enslavement would be the same as it always has, Sex.
A sex android would not be a slave....it would be a tool. Limiting the ability for conscious thought would be a very simple task if we were able to build a synthetic brain in the first place. This is the part of "Blade Runner" I found a bit silly.
Interesting question, I suppose it would depend upon if the clone or android had consciousness and or a soul. If they have either then no they should not be enslaved. If they do not have one or both then yes because at that point they are either beasts or robots and thus not entitled to protections beyond those we grant to any animal or object.
