Re: I'm confused
"I could do what I want. I would have assumed that those writing code for Linux would have had some similar agreement but maybe not."
There are a few differences.
First, whatever any one individual writes is merged with the contributions of many other people in a collaborative effort. Why should you then act unilaterally, possible contrary to what your numerous collaborators want?
Secondly, the purpose of the GPL is to encourage sharing of source code, not to collect fees from users. This is why organisations such as the SFC mentioned in the article aim for compliance, not penalties.
Thirdly people contributing to Free Software projects are not doing so with the intention of profiting from licensing of copyright. They may contribute in order to sell support (e.g. Red Hat) or to have the software support sale of other products (e.g.Intel).
Clearly it's a weakness of the project that the acceptance of contributions is not made conditional on the contributors not taking unilateral actions of this sort.