The AMA doesn't want an oversupply of competition.
https://www.ama-assn.org/press-center/press-releases/ama-fun...
Aren't 99% of unmatched, graduates of sketchy overseas medical schools?
https://www.ama-assn.org/residents-students/match/if-you-re-...
As for overseas medical schools, the National Committee on Foreign Medical Education and Accreditation is supposed to ensure they meet the same standards as domestic schools. I haven't seen any real evidence that they're sketchy.