Right, but that's a trademark case. Trademark and copyright are separate bodies of law and offer different types of protection. Example--Mickey Mouse is an original creation of Walt Disney. Copying a Mickey Mouse cartoon (say "Steamboat Willie") is an infringement of copyright. Mickey is also used as a trademark, standing for the Walt Disney Company. The trademark is registered with the trademark office in the US and elsewhere, and is widely recognized by the public as a mark in Theme Parks, Movies and other entertainment.
If I created a mouse-like character of my own (say "Geoff Gerbil"), Disney might complain if it was too close to Mickey in appearance. This would be an infringing derivative work on the copyright side. If I used it to sell movies, books, etc. it would also be a confusingly similar trademark on the trademark side.
In the McDonalds' case--and probably Tolkien as well, there was no copyright angle at all, it was strictly a trademark issue.