https://foldingathome.org/faqs/project-details/dont-post-source-code/ says:
Posting the source code in a way that would allow people to reverse engineer
the code to produce bogus scientific results would make the whole project
pointless.
That makes no sense to me. Scientific integrity implies free software.
https://foldingathome.org/support/faq/opensource/ gives another reason, which
has nothing to do with scientic integrity and does not make any more sense to
me:
We have not outsourced the client for several reasons, relating to client
reliability and other issues.
