Is xkcd "Think Logically" talking about this site?

I don't disagree about the intended message of the linked xkcd. By a "strawman rationalist with a silly conception of logic" I meant exactly that: a person who assumes that every problem can be solved by "logical thinking" and underestimates the role of expertise. (Since logic alone in the proper sense isn't sufficient to produce results - right or wrong - except in small subclass of problems, this attitude needs some abuse of the word "logic", if one indeed uses the phrase "to think logically" to denote one's own behaviour. But that's besides the point.)

The disagreement arises when you claim that the described failure mode is typical for LW. To me it seems more typical for the rather ordinary sort of crackpots who think they can do everything better than anybody else and when they lose in a direct competition they claim that the rules have been stacked against them (another part the xkcd is mocking). To show that LW is like this, it doesn't suffice to point out that we (for whatever meaning of we) aren't enough influential. You have additionally to show that we are unaware of the difficulties or are finding inane excuses for our lack of success.

Edit: to further clarify, I don't treat LW as means of influencing the world.

I should note this is well-travelled ground; we have this conversation about twice a year.

You are, of course, correct about the failure mode of the adjust-towards-preferred-score strategy.

The vote-without-reference-to-preferred-score strategy has the problem where, if comment C1 has a score 5x higher than C2, someone reading them can't tell whether that reflects 5x as many people reading C1 as C2 and endorsing it about as much, or a 5x higher proportion of readers endorsed it. Which is kind of a big deal, if we want karma scores to serve as feedback about comment quality/desirability rather than thread popularity, which some of us do.

People vary in terms of which problem they're more motivated to avoid, so you end up with both behaviors in the community. When the subject comes up, proponents of adjust-toward-preferred-score typically dismiss the concern you describe by positing that there's no systematic difference between early voters and late voters, and proponents of ignore-preferred-score dismiss the above concern by positing that there's not that much variation in how many people read any given pair of comments. (Personally, I suspect both of those statements are false.)