Ah, yeah that's fair since we're talking about moderating online discussions which are accessible for the public. Although I think the principle still stands for people who aren't approaching the discussion from a principle of neutrality. The people in the audience that you want to change the minds of will react similarly to the way I described, so you might get a small percentage of open minded people but you limit your reach. The extremity of the position also tends to resonate poorly with moderates/undecideds, so I would still suspect that a more reasoned, logical argument would be more effective with the audience. That said though, you make an excellent point.