> What makes telling you to wear different shoes any different? I am just
  > asking you to abide by my rules if you're going to make use of my resources.
  >
  > The GPL does the same.

Couldn't agree with you more, but Microsoft and other proprietary software makers have the same right (to dictate what people can do with their software). For some reason, GNU believes (as RMS has stated in various talks) that not sharing software is immoral.

Now, is not sharing software immoral because (1) it can be copied at no cost, or (2) because you can't morally tell people what to do with the bits once they have a copy of it ?

(1) is nonsense because creating the software has a cost, and anyway, just because something was free to you doesn't mean you can't charge others for it.

(2) is contradicted by the GPL if it tells you what you can do with the bits after you have them.

You can make the argument that free software results in higher quality software, but it's wrong to make a case for it morally as GNU does.