Confused young war veteran fighting with various inner demons and the defeat of his country is reaching for some truth and beauty through painting.
The patron (Max) rejects this search, prodding Hitler to express his inner pain, providing such examples as a meat grinder (which has often been used as a metaphor for the totalitarian state) as part of a performance piece for Hitler to emulate. Tragically, Hitler follows Max's lead and creates the iconography of Nazism...
...and eventually, as we all should know, leads one of the most homicidal performance art pieces ever, which probably ground up Max as well.
What tug of war, Mayr is trying to form Hitler into a hater and Rothman is counseling Hitler into letting out his inner pain.
There was someone (a professor or writer) who tried to appraise the destruction of the WTC towers as a phenomenal performance art piece and then he tried to defend his statement by saying that he in no way supported the action but could distance himself from the horror and look at it detatched. Postmodernism and postmodernists' lack of "black and white"/"good and evil" ended that day although they've fallen back into their old habits.