This is different than "people should write their operating systems to proactively disallow installation of non-free software." Note that the FSF even produces

This is different than "people should write their operating systems to proactively disallow installation of non-free software." Note that the FSF even produces and distributes builds for Windows. Here's an example: http://www.gnu.org/s/mit-scheme http://www.gnu.org/s/mit-scheme . Most FSF projects that don't produce Windows builds directly provide information on where they can be found. Stallman may not want people raising the profile of proprietary software, but he certainly doesn't advocate cathedral-style control of a users' computing platform.