Not to mention, you can't really force them to do anything: they'll just avoid the GPL code, create it themselves, or find something similar under another license.
Isn't it amazing how people come out of the woodwork to point out the force inherent in the GPL never say "oh, by the way, thanks for publishing a reference spec I'm free to use to develop my own code."
As Thomas said, people would be less bitchy, and less holier-than-thou (cough), had Moxie not written any code, or written it and charged an arm and a leg for it.
It's sort of what patio11 talks about. The cheaper the service, the worse the people treat you.