no insult intended. the question comes down to if evolution is the cause behind the diversity of life, why do we have religion: what is the advantage that religion gives that ensures it's survival?
My take is that this thread encapsulates a classic error. It effectively makes the ultra-adaptionist presumption that every feature has to convey some "advantage" for it to persist.
Many things effectively come along for the ride; and many features of organisms are not inherited. It's really dubious to presume that every feature must have an advantage if we just look hard enough, and its especially dubious to look for "evolutionary" advantages in cultural phenomena.
Cheers -- Sylas