Far out guys, it isn't difficult.
The FSF cannot endorse Debian because of two issues. Firstly, it hosts
non-free software on their offical project servers and secondly, they
provide documentation on how to install and manage non-free software.
The first issue is the most objectionable - the second less so, but it's
still pertinent that it is addressed.
At the end of the day the FSF has to draw a line in the sand about what they
consider to be a free vs a proprietary operating system. I think their
definition of a free operating system is adequate as it serves as an
important benchmark for freedom. In my mind, it *is* unacceptable that Debian
hosts proprietary software on their official servers. I think they will
eventually resolve this issue as they did with the binary blobs in the Linux
kernel pre version 6.0. And when they do, Debian ought to be considered a
completely free OS.