How can they trademark the phrase when there are so many examples of prior art in the public domain of the use of this phrase going back long long before HBO's show. Do a google image search for the phrase and you will see its used in lots of memes and similar images to the one produced by this poor child.... I dont understand who's arse got bend out of shape by the picture for this to even ever happen.... Oh wait....
Could this be a publicity stunt to keep the stupid show in peoples mind and in a few days/weeks they will issue a public apology and invite the kid onset for a photo opportunity and to make amends..... watch this space.