GPL (and particularly gplv3) was designed to follow the scope of copyright in what ever country it get used in. If a country choose to have a very wide definiti

GPL (and particularly gplv3) was designed to follow the scope of copyright in what ever country it get used in. If a country choose to have a very wide definition of derivative work then that is the rule that GPL will use, while in an other country it can be much more narrower. This case is also about fair use. Like all copyright licenses fair use give people exceptions when the exclusive right of copyright can be broken.