[Fomite]

I was being charitable to your example, because generally speaking there are no observational studies done before a drug is put up for approval - that's not how the approval pipeline works. The closest I can come up to your example is the occasional off-label use of a drug for some other condition, but the reports from those are largely small n studies. That's entirely different from a series of studies based on NHANES.

Beyond that, in an intentional randomized trial, rather than the 'happy accident' like the Oregon study, the actual control is not 'Nothing' but the medically indicated standard of care. Studies are often required to provide medical care, education, etc. to their participants. I cannot imagine a study managing to get "We deny a bunch of folks health insurance" by an IRB unless it was an externally forced process, like the Oregon study.

Your insult about not understanding statistics, in addition to being off-base, is rather spurious. This isn't a statistical question, it's a public health ethics question. Statistics doesn't really come into whether or not "Keep a bunch of people from accessing healthcare" will get nailed by an approval board.

Also, the FDA often does take observational evidence into account, especially when expanding things like what age range a drug is medically indicated for.