If I were going to join a rationalist club, I would prefer it to be men only. Sexual impulses tend to be counter-productive to the exercise of sound judgment. If we can agree that politics is the mind-killer, the same holds true for sex.

I would be incredibly surprised if we are contained within it. I would be kind of surprised if we're contained to 90% within any 10X larger group. There is definitely a large overlap with Hacker News.

It doesn't sound like fun to you, which implies you didn't try it. FWIW, everyone who participated in the game thought that was one of the most fun meetups we have had to date. I greatly enjoyed the activity myself. The fast pace kept everyone fully engaged in the activity, and the rotating topic kept the conversation from getting bogged down. Cognitive biases are a topic of interest for our rationalist group, doing this alone instead of with a group of friends might indeed be less fun, but as you pointed out still quite useful.