The issue people have is that you are asserting a copyright that doesn't exist. A lot of people have a serious problem with that. They consider it an attempt at enclosure of the public domain.
- d.
Rather, this is a complex issue, based on matters of jurisdiction. IANAL, but Adam's argument is entirely consistent with my understanding of international IP law, with which I have significant experience: to wit, a British reuser who failed to attribute him upon request would have a real case to answer in court. An American reuser would not.
Therefore, rather than edit-war over one-size-fits-all tags, the most sensible thing to do is surely to explain the licensing details on the page in question. This fits perfectly with Commons' requirement for legal reuse in country (countries) of origin to be clearly established.
Regards, Harry
-- Harry Burt (User:Jarry1250)