Thanks for the reply!
I'm not sure I agree that consciousness (or sentience if we're making that distinction) is worthless when considering the morality of exploiting something/someone. I do agree there are more angles than that but they seem on top of something's ability to perceive not instead/despite of it.
Do you have some examples of other things that go into your own moral opinions about slavery?
So, slavery of a human would be ok if enough of us decide (no test, too high a bar) that this human is not conscious?
Of course not. Therefore, lacking or possessing consciousness means very little. Perhaps mostly because we don’t have a test for it, but even so.