Is the list at:
http://www.gnu.org/links/links.html#FreeGNULinuxDistributions
the list of operating systems that meet your criteria? It appears that
gNewSense includes LAME in binary format, and BLAG "recommends" it at
https://wiki.blagblagblag.org/Lame in much the same way OpenBSD does.
In fact, BLAG suggests other unfree programs, such as unrar
(https://wiki.blagblagblag.org/Unrar), even noting that the software is
non-free.
Since I have time to rant but don't have time and resources to download
and install two new operating systems, feel free to correct me if my
impressions are wrong.
I don't think anyone is particularly upset that OpenBSD isn't among the
software you recommend, but to claim that OpenBSD includes "non-free"
software in its ports collection (using your definition of "free") while
claiming that gNewSense meets your criteria is disingenuous at best.