Same thing applies here. In one case the questions are being asked to provide treatment the patient is paying for. In the other it's being done to collect data for a publication.
If my mechanic wants to publish a paper on wear-and-tear on 4 cylinder engines using just the information he gleaned from doing work on cars that I (and others) paid him for, he has caused zero damage to me versus just doing the work on my car.
The same applies here. Patients come in for treatment, and they provide exactly the same questions as if they weren't doing research.
I agree, though, that this study could have been done more easily by accessing the patients' records post-facto. But it's not the IRB's fault that the experiment could have been designed better.
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Also it seems that post-facto experiments are being encouraged over controlled trials, which seems the opposite of what you want from an experimenters point of view.