You would have a valid point if the USMLE were a meaningful differentiating factor in terms of qualifying applicants for residency positions. While some no doubt believe that it is, it my strong opinion that it does not. Looking at a 255 vs. a 225 step 1 applicant (both scores well above passing), I see very little reason why the difference in performance on that test by itself indicates that one applicant would be a better resident than another. The reality is that most graduating medical students are entering residency with the approximately the same skill set. Nearly everyone is intellectually capable as the weaklings were weeded out by admissions or early in M1 or M2. It's not like we are talking about physicians 20 years into our career and applying for a chair position where our CVs actually convey a meaningful track record. Med students CVs are for the most part fluff, and if you can take a step back and look at the big picture, there is very little students can do to while in school to achieve legitimate qualifications as M1-M3 is virtually homogeneous for everybody. It's not like you're evaluating college grads for a job and comparing transcripts between an applicant who took easy classes and made a B+ average vs. an applicant who took rigorous classes and made a B average. The transcripts in med school are mostly pass/fail. They take the same classes. Med students, for the most part, have done the same thing. The only that really differs is their personality and demonstrated interest and aptitude for the field in which they are applying. The rest is just hoops to have jumped through. To me, it seems silly to count up the number of hoops each candidate managed to clear and use that to rank them.
It's actually rather difficult to get a job in industry out of college with a 4.0 GPA. A lot of hiring managers see that as a red flag. They prefer to see a mix of As and Bs with an internship or two thrown in, part-time jobs, and solid letters of reference. You know, a well-rounded person. Hiring managers are keen to pick up on personality traits and the 4.0 guys have to prove they can work with people, be a team player, and be personable. Oddly, because medicine is so tied to academia, numbers and pedigree trump everything else. You can do all the away rotations in the world and get great letters of recommendation proving how capable, focused, and easy to work with you are, but unless your numbers are in line with everyone else, it's unlikely you will be successful because these are not viewed as qualifications. Rather, the important "qualifications" are USMLE score (testing some obsecure biochemistry crap long forgotten), rank of medical school, number (not quality) of research experiences and publications. It's ridiculous.