I'm not entirely convinced that the relationship between crafting a rational argument and crafting a persuasive argument is nearly as inverse-correlational as implied. On average, lies have a higher manufacturing cost (because you have to tread carefully and be more creative), a greater risk (since getting caught will lower your overall persuasiveness), and a smaller qualitative gain (while lies probably persuade more people, I suspect that they persuade less rationalists than civil debate and are therefore less qualitative overall). There are other means of persuading people without making deliberately irrational arguments. If sound reasoning alone isn't tasteful enough for you, why not season your truth with charm instead of coating it in sophistry? Why not leverage charisma or cordiality? You know - the dark art of sucking up?

While fear is often heralded in psychological communities as the most effective mechanism of persuasion, that doesn't mean it's the mechanism of persuasion with the greatest utility. A well-beaten child might obey best, but obedience isn't the only goal of discipline - nor agreement the only goal of argumentation. Personally, I'd rather treat every worthy cause as an opportunity for non-rationalists to exercise rationality than as an excuse for rationalists to manipulate non-rationalists. This tactic might not win every argument now, but it lays a surer foundation on which to build our arguments in the future.