This phrase is uttered by Dad & Brak in the Mobab episode. I'm not sure if it was intentional or not (but I do suspect it wasn't) but "wherefore" doesn't mean "where" but instead "for what reason" so it would seem like it's a fallacy on the writers' part. I know Brak is supposed to be stupid & all but I still have a feeling that it wasn't intentional. If it indeed wasn't intentional then I find it a bit strange that no one involved in the show caught it. If it was intentional, which I doubt, then it's actually sort of clever.
#USELESSNITPICKING