For some jobs, your aptitude should matter. If a test has some discriminating power between people with aptitude and those without aptitude, then perhaps failing that test should really matter. For ATC staff perhaps OCD-adjacent traits are good and ADD-adjacent traits are bad. Maybe you don't want someone with epilepsy in ATC even though that's unfair.
Maybe we all want to be Olympic athletes and a few work hard to become so, but what should happen if we lack some necessary skill?
Bar exam is different because it's just taking a test. Testing is really easy to scale.
This is more not allowing something who dropped out of law school due to academics to be readmitted because law school slots are precious if your goal is to make X amount of lawyers per year.
