That's entirely bogus in its inference. Traditionally, by the time you get into medical school you've earned a ton of As in classes - including chemistry/organic chemistry/P-chem, Physics, biology, physiology etc. In many if not most of those classes, those who went on to medical school outscored those heading to graduate school.
Medical schools themselves don't all grade students, but they are required to ensure that students perform to a level acceptable for becoming a physician. Plus, it is a requirement that medical students pass medical boards I, II, and III before becoming licensed (usually completed before starting residency).
All that be as it may, I absolutely do NOT agree with doing away with the MCAT. The MCAT has been the single most accurate predictor of performance in medical school. They've mucked with it over the years, so I don't know how good it is now, but I think it's a big mistake to do away with it. The MCAT also allows those applicants, who don't come from wealthy families and who didn't go to prep schools and expensive universities, to prove themselves in head-to-head competition against those who have a pedigree.
“by the time you get into medical school you’ve earned a ton of As in classes “
Not true. They can earn a C in a bachelors degree program and still pass and still be accepted into medical school. The Association of American Medical Colleges states they believe a 3.7 is average for entry into med school. I’ve read stories of a C average getting into med schools.
Organic Chemistry was class that determined if you got into Med school. Without an A you had to apply to a school in South America