Give it a rest people. Please. It does not qualify as headline news that an American knows the words to God Save The Queen. Quite a few non-British people do.
I also know the words to God Save The Queen (1st 2 verses - gets a little weird after that), to O'Canada (even the new gender neutral english version ) and to Land of My Fathers (english version & I could listen to the Welsh version all day long). I am neither English, Canadian or Welsh. So, no big deal. And we will not even talk about the U S National Anthem - no one in their right mind would ever sing past the 2nd verse.
So, lighten up folks, this too shall pass.