> A person's ability to survive in a territory populated by Aztecs or Mormons is going to be significantly determined by their ability to conform to group beliefs re: normative behavior

I agree, but I see that as a separate issue from what I was attempting to address. The specific thing I had in mind was about authority figures in a position to promulgate some new idea to society: is it wise for them to spread ideas known to be false but estimated to have positive effects?