This is a linkpost for http://www.meltingasphalt.com/crony-beliefs/
"re-examine your confidence level"
I try to do that. Being part of a community would impede that process for at least some beliefs.
You are probably right about the smaller groups, but there are high search costs, especially since I am an introvert. And for a similar reason it does not bother me much to live alone and without any community.