You've got it backwards. Stallman may be disagreeable at times, but he's no fool. It's written this way to address the root cause of interop issues, which are t

You've got it backwards. Stallman may be disagreeable at times, but he's no fool. It's written this way to address the root cause of interop issues, which are themselves a secondary effect. Of course he wants people to choose GNU, but most importantly, he wants to preserve people's freedom to choose GNU, which means it must not become a second-class citizen to proprietory additions from Apple, Microsoft, or anyone else. If it's portable to GNU, the issue goes away. He says so explicitly.