I don't have the goal of preventing my teenage daughter from having sex (firstly because I have no daughter yet, and secondly because the kind of people who would have such a goal often have a similar goal about younger sisters, and I don't -- indeed, I sometimes introduce single males to her); but I had no problem with pretending I had that goal for the sake of argument. Hell, even if Vaniver had said "simply try to cause more paperclips to exist" I would have pretended I had that goal.

BTW, I don't think that is the real reason why people flinch at such examples. If Vaniver had said “try to win your next motorcycle race” -- a goal that probably even fewer people share -- would anyone have objected?