Well, since you and the other replier seem so intent on taking my comment out of context I will help you.
Yes, there are things that are excluded from being enforced within a contract. But just because one party of the contract wants things to be different, doesn't mean the other party has to allow it. There can simply be no contract and no license given. They are demanding particular things that some software makers are simply not willing to give and as a consequence taking that denial of license as a right to do with the software as they wish.
Can I simply not agree with the GPL and use the software/code anyway? The original parent's argument seems along these lines.