Journalists don't have a history of injecting you with syphilis just to see what happens, though.
Though ENCORE was done with IRB approval, the community is mostly unsure how that was possible...
Edit: although I don't think they change my intuition that it's strange that high-risk invasive procedures that people expected to cause grave injury are dealt with by the same oversight mechanism as interviews (even though I'm very convinced of the ethical importance of strong confidentiality protections for interviews).
Second edit: I'm also aware that IRBs aren't only inspired by Tuskegee and Nazi experiments, but also by stuff like the Milgram and Zimbardo experiments which didn't involve invasive interventions.
Though, every IRB is different. Which is another problem!
1. People who should have been treated weren't.
2. As a result of #1, more people would have been subsequently infected.
Additionally:
3. Distrust in healthcare is engendered amongst a marginalized population, with potential to lead to further incidences of undiagnosed ailments.
The net result is similar, more people are infected than would otherwise have been. Just because the infection mechanism is less obvious doesn't necessarily make it less bad.