Classic misinterpretation of their own mores and their origins. Urine therapy was and still is widely practiced around the world to improve skin, prevent bacterial overgrowth, and recycle urea / minerals. Technically urine is sterile when it exits the body, and contains little to no toxins unless there is a huge accumulation being herbally dumped. Not suggesting you get out and do it, but there *was* an understanding about why it was useful, much like how chinese medicine came around with thousands of years of testing and experimenting. This "evil eye" thing is like the "don't eat the pigs" anti pork thing, which came around because the pigs were formerly used to clean the streets and so their meat was loaded with trash, which would make you sick. Hence "it's in our religion not to eat pork" Same with hindu "no beef" thing. If you ate all the cows, there'd be no way to get milk, make cheeses, birth new cows, etc. SO, the wiser people of the era, not being able to get this idea across to the dumb-ass locals, would intice them via some religious mythos so that they wouldn't cause everyone else problems going zombie mode if they stupidly ate their only food supply