[gobengo]

millenia is not very much time to be applying inductive reasoning about future odds.

absence of evidence is not evidence of absence

[olodus]

Millenia is however a bloody long time to have daily diarrhea. But I commend them for trying. Good luck.

[fluoridation]

The question is whether drinking contaminated water has a survival advantage. It could have one if clean water is so scarce to the point that you're more likely to die of thirst before reproductive age than of bacterial infection.

[morkalork]

Why don't you go out and drink raw water for a while and report back after.