I couldn't find where I saw/heard it, but I swear I saw a blurb about PRIME drinks containing polyfluoroalkyl, which is what allows jackets and tents to repel water..
Eh, if someone comes up with such a comparison it immediately tells that they don't know what they're talking about. Like, linseed oil was also used for waterproofing (oilskin), yet it is quite healthy. Other applications/occurences of a substance simply don't tell you anything about it being good or bad for you.