I've observed the same thing in video games with group activities. People sit in party finder waiting for somebody else to organize a group. They could make the group themselves, but they don't. They just sit there and wait until somebody else does it.
In real life I can understand this apprehension a lot more, but in games it's the difference of a few clicks and picking and choosing who gets to join. And yet a lot of people don't want to do it. It's quite curious.
I wonder if it's related to who is willing to organize things in real life as well. Maybe some people are just more driven to organize things?