But for those who don’t, and who don’t see beyond the surface veneer of “we’re defending Earth from invaders”… It looks a lot like AmericaWorld, where everyone is happy and free and kept safe from the nasty aliens.

If you don't think of it as a military dictatorship (remember, this is not the real world, it's fiction and people read into it whatever they want) then super earth is the good guys.

Super earth is painted as the most pristine fascist ideal of the polity united under a single uniform banner (because everyone who wasn't in line has already been purged or will be, shortly), why would your average normie (who by definition won't be strongly objecting on principle) ever oppose that if not for the means it was achieved with?

Most people come into fiction assuming the author agrees with whatever they think.

That's why you can hear lefties praise Ocarina of Time as anti-monarchist because Link is deposing Ganondorf, when it's obviously restorationist since Link is actually reinstating the rightful king of Hyrule, not ending monarchy altogether.

That's also why preachy, obnoxious, clumsy propaganda that bludgeons you with its political stance sells about as well as a kick to the teeth. Anyone who agrees will be bored by hearing repeated talking points, and anyone who doesn't will despise the message, not be moved or convinced.

Good art with a political message makes you actually come to the conclusions the author came to through the process of enjoying the art and having the experience the author has built in it.

For instance, by humanizing a character with ideas or traits you find distasteful.

Like the original Starship Troopers book, whose main character is not a blonde blue eyed all American boy, but Tagalog-speaking Filipino Johnny Rico, whose ethnic background Heinlein hides until the final chapter to make his 60s mostly WASP teenage boy audience identify with him, so they can have the realization that in a society that does not care about race they would not even realise which race the characters are until something practical comes up (his natively speaking Tagalog in this case), which was exceedingly anti-racist for the 60s.

Bad art tells you the political conclusion you should reach then calls you a bigot for rejecting its message. It's less than worthless as a political tool, it's actively detrimental because it creates the kind of staunch opposition and attempted purges we see weekly at this point trying to get woke shit out of media, the same way we had those in the 2000s with conservative trash like the "drugs are bad and a single joint will ruin your life" we would see in sit-coms every fucking season.

Every side does this when they have hegemonic control of media production, and everyone who isn't aggressively brainrotted eventually gets fed up because not only is it not helpful, it makes for bad art even when you agree with it.