Here is my opinion on the issue. If others use contents from Wikipedia, let them do so.
Suing them or intimidating them by threatening to appeal to authority to use force on the users of information will make those here no different from the corporate mafias which claim to own informataion and hence others' brains.
It will be a violation of intellectual liberty to claim ownership over something that is published. Once you publish it, it should be for public. Don't give me legalese and try explaining what GPL means. I know what it means. The whole idea of it originated as something antithetical to the so called intellectual property "rights" and there were causes to protect those using GPL from being preyed upon by these predators.
Just because someone states on their page that they have the copyright doesn't mean they have the copyright to the specific arrangement of words. Let us not be mean-spirited. If you really believe in freedom, you should believe in freedom to claim anything silly too.
-libertarian
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