Hmm, really ? Can you offer some examples ? I've browsed some of the articles on the site, and they didn't strike me as unduly biased -- unless snark counts as bias. But then again, I'm not sure what you mean by "controversial"; some topics, such as creationism or global warming, are controversial in mainstream culture, but fairly mundane here on Less Wrong.
Knowing Vladimir [1], he likely means that they use exposition of stupid things like Conservapedia and Christian fundamentalism to bash all kinds of right-wing thought, especially the American variety, while not investigating liberal cognitive failures enough.
http://rationalwiki.org/wiki/Conservative
(Note that the article above, while ridiculously biased, does have one good section, the one on the relativity of the term. And, aside from any ideological neutrality, even a moderately smart left-wing fanatic wouldn't list Ann Coulter among "Prominent con...
I am not sure whether this has been posted here before but I came across this: http://rationalwiki.org/wiki/LessWrong
What do you think about RationalWiki in general, and their opinion regarding LW?