The Siege of Sarajevo killed 20% of the population, a horror most of us can scarcely grasp, yet those who survived it look back on the siege as a period of unique happiness. Why should that be?
G. K. Chesterton noted that one shouldn't remove a fence until you understand why it was there in the first place. This is a great analogy for the concept of the traditions which have been passed down to us by religion. Technology allows us to remove a lot of fences, but are we sure we understand why they were there to begin with?
Expanding on Nick Bostrom's metaphor for technological development — it's like drawing balls of various shades from an urn, and if you ever draw a pure black ball, the world ends...
Clearly there are some traditions which should be abandoned. And just as clearly there are some which should be preserved. But what are we to do with the vast majority which fall in the middle?
There's significant evidence that traditional practices were beneficial and adaptive. But many reject traditions as relics of a barbarous past. How do we make that determination?
Religion is a very old technology, and the wisdom contains is often hard to identify. This is unlike the technology we create intentionally, where the goal is always obvious. When these two technologies come into conflict who should we decide between them. It's easy and attractive to go with the new, but by dispensing with the old we may be incurring harms that will only manifest years or decades later.