There are lots of things that we could do to speed up scientific progress, but they're not all necessarily ethical. Making private individuals' medical records effectively public is quite possibly one of those things.
If you don't want to disclose your medical record, fine. But don't expect others to funnel billions into you just to make your dream of going to space come true.
Combined with the notion that I'm sure the paper will be anonmised and re-released. I'd even bet this is a non-issue. (Assuming the assertions previously made in this thread of course).
So with all due respect, to me that means your second sentence may well be replaced by "If you want to make the disclosure of medical records a requisite to be an astronaut, don't expect too many qualified applicants to show up for the job".
The know that they are test subjects. Read "An Astronaut's Guide to Living on Earth", and they know it's a part of their job to be test subjects.
As long as it's space-related, the astronaut's medical history is really anything but private.
What NASA could be trying to do is limit press access to individual astronauts because they are still entitled to their private lives. In this case, yes, they will be concerned about personal details leaking.