Disney employs Donald Duck as a means of celebrating American ideals of freedom and liberty, presenting a detailed depiction of Adolf Hitler and his regime’s militaristic approach. The film primarily uses music to mock Nazi ideology and also targets the other Axis powers. We are taken to "Naziland," where there are apparently no slaves—only citizens working there, regardless of their feelings! There's a focus on munitions and photographs, possibly more of the latter for displays of allegiance. It seems like an early illustration of personality cults. The initial impact is considerable, but the repetitive nature causes it to lose momentum; while the recurring sequences convey the intended message, they perhaps overemphasize it, leading to Donald experiencing a mental breakdown and visions before… Like many cartoons produced in the U.S. at that time, it became increasingly dedicated to educating people about the justifications for fighting World War II. The goal was to strengthen feelings of dislike towards their adversaries within the country and reinforce what they were defending—and it achieves this successfully, incorporating some humor along the way.

Source on TMDB