I know the Debian project only officially supports art assets that are in the public domain or licensed under a Creative Commons style license, but I can't imagine they actually consider these things software. Can you show me where they call these things software? Because if that's true, I find that use of terminology to be quite ridiculous.
Stallman thinks all users should be able to share and remix artwork freely, btw.
I'm well aware of Stallman's subtle and well developed stance with respect to human freedom and software, art, and documentation and I think it's perfectly consistent and reasonable.
The Debian project has adopted a stance that everything distributed as a part of the project should come with a set of rights, whether it's executable programs, game textures, or documentation.
Every part of Debian must conform to the Debian Free Software Guidelines, even if it's just a text document describing a library. So text files are considered software in Debian for purposes of the DFSG. That's all I was implying by saying that Debian considers non-executable parts of a project to be software.