Speaking as a cat, there are a lot of people who would like to herd me. What makes your project higher-priority than everyone else's?

"Yes, but why bother half-ass involvement in my group?" Because I'm still interested in your group. I'm just also interested in like 50 other groups, and that's on top of the one cause I actually prefer to specialize with.

...It seems to me that people in the atheist/libertarian/technophile/sf-fan/etcetera cluster often set their joining prices way way way too high.

People in the atheist/libertarian/technophile/sf-fan/etc cluster obviously have a ton of different interests, and those interests are time/energy exclusive. Why shouldn't they have high requirements for yet another interest trying to add itself to the cluster?