OK, now I'm utterly confused: I had meant to refute the claim that discussion of slavery was a purely modern thing by providing counterexamples of ancients who

OK, now I'm utterly confused: I had meant to refute the claim that discussion of slavery was a purely modern thing by providing counterexamples of ancients who had found that economic system worthy of reflection and discussion, so I fail to see how introducing yet another modern (parochial, yet!) thing may be relevant? (enthymemes can be effective, but they are utterly reliant on people knowing what the hell your middle term may be)