[watwut]

> Even the most crystal clear stream will have some sort of wild animal refuse in it that could leave you sick for days.

When you are local never ever moving out of place you do know what is upstream or in well. This "had no idea cows are up there" thing is modern hiker problem.

> the average person's distaste for drinking plain water is somewhat universal across time and cultures and might very well be a human adaptation.

There is absolutely nothing universal about that. Instead, drinking water seems to be universal accross cultures.