Perhaps you did not pick the correct biases? Remember the way that Rational!Harry convinced Draco Malfoy? You need to start small. First produce a belief that your methods lead to more correct results, then build up more and more biases and have them create a more accurate picture of the world. Then when you have a critical mass, go for a bias that is more central to their worldview. You need your ideas to be strong enough to win the inevitable contradiction war.

Consider that LessWrong is a self selected community. People come here, read the site, and only stay if they agree. What if out of 10000 potential members the site only convinces 5% or 10%? And furthermore the people who disagree here don't have the power to control the conversation so as to throw off people on the fence or people who have a small initial agreement.

Personally my anecdotal experience, re: convincing people of atheism, is that you need to focus on doubters and even then you maybe only get a 1/10 ideal result. Group conversions are unlikely to be effective. Maybe aim for a few people to talk to you afterwards about more info on the topic.