Beyond that, I'm further surprised that the LessWrong community at large was so enthusiastic in upvoting these insights into how to seduce impressionable people into a false, irrational, and personally costly religious cult.

Huh? calcsam wrote about ways to spread rationality more effectively. I upvoted his posts because I felt that advice is valuable, and that we have a lot to learn from organizations that have far more experience in spreading their beliefs.

Yes, Mormons use those techniques to teach people irrational beliefs. But to say, simply because of that, that the techniques are "insights into how to seduce impressionable people into a false, irrational, and personally costly religious cult"? That's like somebody making a post about the best ways to earn money, and somebody else saying they don't want on LW "insights into how to help false, irrational and personally costly religious cults run their operations" (because cults, too, benefit from having money).