Don't worry I'm the last person that needs convincing about the significance of history, I'm a history undergraduate! And yes religion has been at the centre of nearly all major events and nearly all societies for the whole of history. But in the modern era I think we've moved away from that, religion is less important than it ever has been. However I see your point, if you wish to use the word spirituality in a non-religious context ie. more of a feeling underpinning a movement, then yes it is essential - I just don't like using that word. Just the problem of semantics I suppose.