Actually, I believe the optimal utilitarian attitude would be to make fun of them. If you don't take them at all seriously, they will grow to doubt themselves. If you're persistently humorous enough, some of them, thinking themselves comedians, will take your side in poking fun at the rest. In time, LW will have assembled its own team of Witty Defenders responsible for keeping non-serious accusations at bay. This will ultimately lead to long pages of meaningless back and forth between underlings, allowing serious LWians to ignore these distracting subjects altogether. Also, the resulting dialogue will advertize the LW community, while understandably disgusting self-respecting thinkers of every description, thus getting them interested in evaluating the claims of LW on its own terms.

Personally, I think all social institutions are inevitably a bit cultish, (society = mob - negative connotations) and they all use similarly irrational mechanisms to shield themselves from criticism and maintain prestige. A case could be made that they have to, one reason being that most popular "criticism" is of the form "I've heard it said or implied that quality X is to be regarded as a Bad Thing, and property Y of your organization kind of resembles X under the influence of whatever it is that I'm smoking," or of equally abysmal quality. Heck, the United States government, the most powerful public institution in the world, is way more cultish than average. Frankly, more so than LW has ever been accused of being, to my knowledge. Less Wrong: Less cultish than America!