Forbidden Anthem of Defiance does have some satirical jokes here and there. But overall, there is no underlining political message behind the film. However some fans think that the movie is more political than actually is.
Justified: The creators, consciously or not, added some political meanings to the work.
Zig Zagged: Joke #1 in Forbidden Anthem of Defiance is nonpolitical in nature, but mistakenly perceived as such. Joke #2 is correctly interpreted as a joke about a then-current political issue. Joke #3 was designed as a political joke, but the majority of the audience doesn't pick up on the subtext. Joke #4 is nonpolitical and everyone who sees the movie recognizes it to be so. Repeat until the end of the film.
Forbidden Anthem of Defiance is openly a political film.
Or alternatively, the viewers are sure that there's no political message behind it.
A character encourages the audience to find something political about the film.
In-Universe example. Emperor Evulz twists Bob's words to make it look like he's in favor of a controversial political ideology. So people don't agree that ideology, but hate Evulz, won't side with the rebellion.