While corporations dominate society and write the laws, each advance in technology is an opening for them to further restrict its users. - Richard Stallman

The programmers who write improvements to GCC (or Emacs, or Bash, or Linux, or any GPL-covered program) are often employed by companies or universities. When the programmer wants to return his improvements to the community, and see his code in the next release, the boss may say, "Hold on there — your code belongs to us! We don't want to share it; we have decided to turn your improved version into a proprietary software product." Here the GNU GPL comes to the rescue. The programmer shows the boss that this proprietary software product would be copyright infringement, and the boss realizes that he has only two choices: release the new code as free software, or not at all. Almost always he lets the programmer do as he intended all along, and the code goes into the next release.

All intellectual property rights are just licenses granted by society because it was thought, rightly or wrongly, that society as a whole would benefit by granting them. But in any particular situation, we have to ask: are we really better off granting such license? What kind of act are we licensing a person to do?

Why is it bad to use an unauthorized copy of a proprietary program? Because it's proprietary! So an unauthorized copy is almost as nasty as an authorized copy of the same program. They are both nasty because they are proprietary. The users don't have control over them. If they pay developer – that makes it worse, because they are rewarding this delinquency. That's why the authorized copy is worse. But they are both bad because they are both proprietary software. If you want freedom, you have to get rid of them both, because they both control you.