So this is one of the latest stupidities to become a fad. I suppose the past history of various civilized societies in which people avoided "raw water" has much as possible and got a lot of their fluids via drinking ales, beers etc., because "raw water" was a health hazard has past these idiots by.

The bottom line is drinking "raw water" is often a significantly hazardous undertaking unless it is from a pristine spring.