It's not by any means and I'll give him credit that the film has managed to be have an infinite number of ways to interpret it.
...But in typical Doug fashion, he also completely misses the underlying point of the movie and instead pulls a message out of his ass. The main, definitive point of the movie was to 1.) Have compassion for broken, mentally ill people, 2.) Understand the hypocrisy and craziness of society/the media/etc., and 3.) Show Arthur's fall from grace in how Gotham itself created a monster.
Doug does this all the time. Even if he's right on one of the many interpretations of a film, he always picks the most random ones to follow. For example, he thought that Grave of the Fireflies was about one's pride overtaking reason to the point of harming loved ones when the movie is VERY on the nose about how destructive war is on innocence and the lives of civilians living in WW2 Japan.
He does this shit all the time and it annoys me.