What it does mean is that if a potential pre-med is choosing an undergraduate college, the existence of a pre-med committee that does gatekeeping for medical school applications may be a relevant factor.
A. If the pre-med will want to try to apply to medical schools (at considerable cost in time and money) even with a lower chance of success (i.e. would be weeded out by the pre-med committee’s non-support), then s/he may want to avoid colleges with a pre-med committee that does such gatekeeping.
B. If the pre-med wants to know earlier whether the probability of success is high (pre-med committee will support) or low (pre-med committee will not support) in order to know earlier whether to switch to another path without spending time and money on a probably futile application cycle to medical schools, then s/he may want to prefer colleges with a pre-med committee that does such gatekeeping.