What it says about human nature is this - we're not that far removed from our baser barbaric instincts, but we are not beholden to them. We're flawed, but we can change. That even if we only snip away at parts of tyranny and enshrine others, eventually later generations will snip out the sins we enshrine. Our founding fathers were better than what came before, but were very wrong as well. We are better than they were, but we too are preserving our own ills. And with luck, future generations will be better yet.
But it does look quite bleak right now in the short term.