Suletta is sometimes blamed for stuttering, for being apologetic and breaking down emotionally due to thinking it's her fault for everything, for often behaving in a very awkward, childish way. But this is what makes her a real character, like a real life shy girl, with emotion bleeding out of your screen. She is not a perfect personification of some ideal or just a cog in some political conspiracy, and is scared by war, politics, and death, but went to the academy to achieve her goals and fulfil the path set out by her mother and accidentally ended up playing a role in something much bigger than expected. This is what makes me sympathize with her so much and enjoy seeing her grow to protect her friends and Miorine. Similarly, Mirione is fed up with reality, has to face bullying and her mistreatment by her parents who want to give her as a fiancée to the winner decided by mobile suit fights at her school (which shows the idolization of militaristic power, the commercialization of human life and the sexism driving her society). Because of this she wants to flee the academy alone, but by time she grows and takes on responsibility to protect Sulleta and her friends. The relationship between Sulleta and Miorine largely drives the series and is one of the most wholesome and positive romantic relationships I've seen in sci-fi anime, while also a positive LGBTQ+ message about lesbian love. The childishness and shyness of Sulleta is juxtaposed with Miorine's apathy she has developed towards the world she sees as unfair, and so they both grow massively.
The Earthians who ally with Miorine and Sulleta despite the mistreatment and discrimination they face, many of them war orphans from Earth, manage to build a company that does good to society, thus finding their place in the world and improving as people. Even the villains are seen as real people who came to their unethical actions due to real life hardships and negative emotion, as well as wanting to improve the world in a messed up way. Though I agree the anime makes us sympathize with them too much, even when someone murders thousands of people.
As to the political message, I think it is one of the most progressive in all of anime. Many popular anime promote fascist and sexist ideas, at least implicitly / subliminally. Other anime, again, denounce actual economic reform in favor of some pie in the sky utopia. Finally, many anime are conspiratorial in nature, using some sort of greater conspiracy theory to drive the plot and cause intrigue, while taking from the political message, that war and fascism have real, socioeconomic causes. Here, the technocratic monopoly of the Benerit Group is explicitly criticized as the cause of war and authoritarianism, and their immense economic power is seen as an evil, driven by the commercialization of human life and the extraction of profit from war. Similarly, racism, authoritarianism, the idolization of military might and duel results, all characteristics of fascism, are criticized. At the same time, the alternative proposed isn't some equally extremist form of reverse racism, of Earthians towards Spacians, but an all inclusive economic system where war is no longer necessary and everybody human has equal rights. My only gripe with this as a socialist is that it doesn't completely denounce capitalism, but only an instance of it.
