The analogy isn't effective (outside the ingroup where it originates) unless it's credible; throwing it around in situations where it isn't in no way guards against the possibility of a recurrence of Nazism, or one of its less famous but often equally nasty companions in 20th-century totalitarianism. In fact, I'd say it's probably actively detrimental, as it makes the accusation less punchy when and if we do start seeing a totalizing popular movement that openly preaches extreme prejudice against an unpopular group of scapegoats.
That's not to say that these kinds of mass movements aren't worth studying or analogies to modern movements can't be made; they absolutely are and can. But crying Nazi without commensurately serious justification can only cheapen the term once everyone catches on. Who cares about having one more political slur?
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.