You've been reading far too much of the Why Stanford? thread. As have I. And, no, that doesn't make sense... I feel as if the "weeding out" is immensely overexaggerated; and it's all about how you push youself once you're there. If you really want to be a doctor, then you'll manage to overcome the herbicide. I can guarantee, however, that whatever challenges you face in the pre-med program will increase ten-fold once you're in med school. And it's always good to be prepared.