A well-beaten child might obey best, but obedience isn't the only goal of discipline - nor agreement the only goal of argumentation.
You've got the wrong kind of fear there-- the effective use of fear is to make your listener afraid of some third party or event, not to make them afraid of you.
If you make people afraid of you, they might give in, especially if you have physical power over them. You might get useful compliance that way. However, you're also likely to get people to avoid you if they can, or to push back compulsively.
Scott, known on LessWrong as Yvain, recently wrote a post complaining about an inaccurate rape statistic.
Arthur Chu, who is notable for winning money on Jeopardy recently, argued against Scott's stance that we should be honest in arguments in a comment thread on Jeff Kaufman's Facebook profile, which can be read here.
Scott just responded here, with a number of points relevant to the topic of rationalist communities.
I am interested in what LW thinks of this.
Obviously, at some point being polite in our arguments is silly. I'd be interested in people's opinions of how dire the real world consequences have to be before it's worthwhile debating dishonestly.