Be grateful that you have a clean water supply, and lend a hand here in adding to the knowledge base that could, potentially, be used to save lives on a global scale.
I think we've got two separate issues here. One, backpacking in the more remote areas of America itself, few water issues are found, despite previous bad press. Two, hundreds of millions if not billions of humans live in reasonable proximity with other humans and have to deal with the lack of centralized, reliable water and sewage systems.
Brum, I'm going to hazard a guess that you deal with the second situation a lot more than I do, for example. For some of us, me namely, the only concern with water purification is when we head out on a trip into terrain quite different from our daily life. I don't bat an eye at my tap water or the tap water across most of the US. It tastes weird, but my body doesn't notice the difference. What you say about the different villages and their water supplies is absolutely -fascinating-.
That said, I'm pretty passionate about water purification both for myself and for those who don't live with a nice sewer and water supply as I do. <img src="/forums/images/graemlins/cool.gif" alt="" />