I think the bottom line in David’s main thesis is really the following. The other parts to it are only relevant if the following is true. And if this part is true, then his thesis is extremely relevant.
He basically contends (and I will have to paraphrase and please correct me if I got the gist wrong - or if it could be stated better than here, too):
The main problem with religions isn’t that they are probably false or bogus. (Why would any non believer give a hoot?)
Religions indeed do much good for society.
Religion’s main detriment is when it misdirect the talents of geniuses or would be geniuses towards what the individual ends up doing with his life instead of in ways that might better serve ( humanity or science for sure - in the larger scheme of things).
It is basically about opportunity cost. (defined:
http://en.wikipedia.org/wiki/Opportunity_cost)
edit - my link didn't work , if someone can post a link for me, please? I am an idiot.
If I got right what David is suggesting and if I am wrong about religion and if he is right about the opportunity cost, we are still left with the question - so what? But, we can answer that by saying - well if one would have been Christian discovers something else that leads us to (or further in) the “right” direction of things, then you got something. If no God, anyway, then you just got more of the same (IMO). If towards another concept of God, then you probably got something.
Aside:
Btw, I really think he is wrong about opportunity cost. I don’t think Christians, for example, as a rule give up a science that they would have had a passion for because of their religion getting in the way. If we agree that the above is the main issue, then we have to study if religion is distracting would be scientist. If so then religion needs to better teach its members that the two are not mutually exclusive. If not the case, then a study of why scientist are so mistrusting of religion is in order (aside from the surface scratching we have done here. I really think it is because few have actually studied higher theology. ) I am not in the science social circles, but simply reading (for example) Bertie Russell’s text here briefly, he had no clue about Christianity.