Just a note, the only way to add the non-free section in Debian involves typing the word "non-free" into a particular spot on a text file, or if using the GUI interface, to edit the entry for the Debian repo to type "non-free" into the "Components" textbox in the "Edit Source" dialog box. So it's not really possible to accidentally enable the non-free repository. I honestly tend to disagree with the FSF's classification of Debian for this reason.
I'm not happy about the Debian<->FSF situation either, but note that if you want your Emacs install to include all the online doc with which it should normally be accompanied, you have to add the `emacs-common-non-dfsg` package from the `non-free` section.
So, the FSF ends up wanting to encourage Debian users to add the `non-free` section to access the docs of several important GNU packages.
There's also the fact that the wiki.debian.org includes several places where they encourage users to install `non-free` packages.
I wish the two associations could take a more pragmatic look at the situation to resolve these disagreements.
Stefan