I mean tons of retrospective studies are literally "IRB exempt" (and highlighted as such in their methods) where no explicit consent is required or needed. Physicians doing case reviews don't need consent of the patient this work. Doing retrospective analyses for defining clinical phenotypes on patient data that has been aggregated isn't needed either. Collecting clinical MRIs to do deep learning doesn't require an I…
In practice, sure, but that's not what the spaghetti of rules that one is compelled by law to follow state. This disconnect is the whole point of the article.