What is interesting about this is how stories can take over and give a singular cohesion to madness that would otherwise be lacking from the normal confusion and lack of direction attendant to that unfortunate condidion.
I use the word 'stories' loosely - as the article notes, the effect can be produced by architecture, paintings, possibly even music.
Maybe Hitler was suffering from Siegfried syndrome. His gestures seem to have been lifted wholesale from opera, and the cadences of his ravings seem to map well onto Wagner's music.