While there are STEM requirements to be eligible for med school, there is no requirement that an applicant be a STEM major. There are plenty of students with BA degrees going off to med school every year.
There is no need for a med school applicant to be a graduate of a college renowned for STEM disciplines. In fact, BC sends a number of its graduate to med school every year.
There are a number of factors which differentiate these 3 colleges, but a STEM reputation for pre-meds is not one of them.