Not a good argument as the aristocracy Jefferson represented were slaveholders. Haven't referred to the civil war at all in any of my comments. The Republic Federalists had created was radically altered by Jefferson's faction almost 60 years earlier. Everything else flowed from that.
That your best card? You're going to have to get another one -- slavery had been around for, oh, 7000 years or more (as an alternative to eating captives), and the argument that Slavery Is Not a Good Thing dated back only to the exertions of William Wilberforce in England. Which was a long, uphill slog for Wilberforce, given that even Leviticus and Deuteronomy (and Numbers, I think) contained moral guidance for the keeping of slaves.
So what's your point? Other than to judge ad hoc 18th-century men by 21st-century lights ? Which aren't all that bright either, come to think of it.