Well, first of all, it's "politically correct", not "political correct" and "karma" isn't a proper noun. Second, even if you were typing the correct phrase, that's not what it means; political correctness has a meaning that doesn't involve any reference to toeing the Less Wrong party line.
Ignoring the surface characteristics of the comment, karma doesn't control ideology. (If it did, I couldn't be a loud deontologist and come in third on the entire blog, as one salient example. In fact, most of my comments professing deontology have been upvoted.) Well-presented and polite nontrollish comments arguing for nearly any position can score positively. Karma is a control mechanism for topicality, tone, tidiness, visible good faith, etc. People sometimes vote for agreement, but there are enough people here that it usually comes out in the wash, and the phenomenon is dramatically less likely to bury a comment that is written kindly than one that's aggressive or snide.
...And since the benefits of karma have already received attention ad nauseum all over the site, I didn't want to spend those minutes on this redundant comment, but you rendered valueless my other mechanism of disapproval.
I just watched Transcendent Man about the singularity and Ray Kurzweil in particular. It's well-made, full-length, and includes the most popular criticisms of Kurzweil: that his prediction timeframes are driven by his own hope for immortality, that the timescale of his other predictions are too optimistic, that his predictions about the social outcomes of revolutionary technology are naively optimistic, and so on. Ben Goertzel and others get much face time.
You can rent or buy it on iTunes.