Is there a good reason for this? Many other countries let you go straight to med school after high school. But for some reason we make it so that you need to spend 4 years doing an undergrad degree if you want to become a doctor.

Additionally, although not science, we do the same thing with law school. This one makes absolutely no sense to me. Why would a future lawyer need to get some bachelors degree before going to law school? At least for medical school you have certain classes that make you take, this is not the case for law school.