Okay so K-97's post, which was excellent btw, reminded me I need to explain something. At the end of my first post, I introduce the Grey Elven concept of a jacta, an error in thought. All a jacta is is a logical fallacy. Ad hominem, argumentum ad populum, argumentum ad temperantiam, appeal to authority, slippery slope, they are all jactas. The Grey Elves, being a rational people, are obsessed with formal logic. The slippery slope jacta, the nel dwekar, happens when you argue against a position based not on that position, but on its possible (often questionable) consequences. Slippery slope is common as an argument against gay marriage when the con position claims it will lead to bestiality. That's slippery slope.
The irony in that scene was that the elf actually used the slippery slope!! His argument contained the fallacy when he argued that the fae can not be given any freedom because it will lead to full integration. He essentially used that fallacy to manipulate the mayor the way a sophist rather than a logician applies logic.
Don't worry if the above is Greek to you. Philosophy and logic is not an overarching theme of the game, it's just a theme for the Grey Elves.