The Call of Duty games were never exactly known for their insightful political commentary, but the sheer, self-righteous lack of self-awareness apparent in Infinite Warfare really does make one wonder. War is an ugly business: realistically speaking, it's hard to find "good guys" on the battlefield. Every side of a war believes themselves to be noble and justified in their actions (or they wouldn't have gone to war) and both sides would like to believe that they are going at it against an enemy who is immoral, evil, or at the very least wrong. We live in a cynical, reflective era in which people are having a harder and harder time accepting simplistic, hyperpatriotic narratives of "good versus evil", by which one's army is made up entirely of morally upright heroes of light and the enemy is a Card-Carrying Villain. We've grown mentally callous from images of atrocities committed by both sides and the human suffering among the enemy. That is doubly true given the relative lack of "real" wars in recent times, of national army against national army. We live in an age of a war on terror: armies, generally well-equipped with overwhelming, technological firepower, forced to cause massive collateral damage as they go against militias hiding among local populaces who have been usually living in deplorable conditions even before some big national powerhouse stepped in to start bombing them with drones. Said militias are often painted by the media as fanatics, but even so, it's hard to find a news network nowadays with even the slightest pretensions of objectivity who wouldn't at least dedicate some token thought to what justifiable motives they might have: after all, Your Terrorists Are Our Freedom Fighters.
Infinite Warfare seems to, very blatantly, do away with all that. From the very beginning of the game, literally the prologue, we are all but force fed an extremely one-sided wartime narrative: UNSA good. SDF bad. From the get-go, there is no moral complexity involved whatsoever. The opening sequence, which supposedly provides some quick historical background to the conflict, tells us that the Earth was desperate for resources, and as patriotic music plays in the background, an inspirational image is shown of the no-doubt heroic people who left it to save humanity from starvation... but rather than go over what was no doubt a complex and prolonged social and political conflict following the colonization of Mars (which, mind you, is depicted as a shadowy, blood-red planet as the music suddenly takes on an ominous tone, in the propagandistic tradition of Riefenstahl and Goebbels), the very next line we hear is of how, apparently with no true motive, it rose against the Earth committed to all-out war. The SDF's motivations are completely, brutally glossed over. The message is clear: they attacked us because they are evil. In the very first mission of the campaign, we are quickly (perhaps too quickly) introduced to the warring sides in a contextless situation: the UNSA, represented by a team of heroic, brave special-forces operators (who are, of course, moral and sympathetic, and are thus express internal conflict over the actions they're forced to commit elevating them over the mindlessly brutal SDF only to be reassured that it is all necessary for humanity's survival) is on a mission to stop the SDF from producing a powerful weapon (note how the UNSA never, say, attacks an SDF population center: they only hit military targets. It's the inhumane SDF who does the opposite. Note also that the weapon is specifically stated to be based off of stolen UNSA schematics: even when it comes to weapons, the destructive SDF are, of course, incapable of true creativity). They are confronted with faceless, aggressive enemy troops possessing an edge in firepower in the form of giant robots (this is a clever propaganda tactic: the person behind the narrative knows that UNSA actually has the upper hand militarily, so in order to avoid them being seen as overpowered bullies, he makes them into underdogs by presenting an isolated case in which they are). The UNSA soldiers fight valorously to protect one another and finish their mission but before they're able to, they're stopped by the SDF leader, Kotch. An entire essay could be written about the mind-boggling number of propagandistic techniques used to make Kotch into an avatar of all that is evil (in fact, lines could be easily drawn between his depiction and those of figures like Saddam Hussein, Joseph Stalin and Hitler), but the following spells it out best: the very first we see of him is shooting one of his own men while telling to the viewer, to their face, that care (i.e. a sympathetic, human emotion) is a weakness. The contrast couldn't be drawn more sharply if they'd given the UNSA soldiers halos and drew Kotch with a pair of pointy horns.
The following scene, from a propaganda point of view, is even more fascinating. Like nationalistic films aimed at the German population during the early 1940s, it seems to be tailor made not to instill violent patriotic fervor (as, at this stage, such an aggressive technique might turn the audience off) but to subtly convince them of the necessity of future, more radical action. It shows us a dialogue between two members of the UNSA military: one who pushes for military action against the SDF, and one who argues against him. It's worth noting that, lest any member of the imaginary audience develop a shade of doubt, both are actually in agreement on that military action is needed, but one has his hands tied by diplomats and politicians. almost as if to say "If only someone was voted into power who'd have let us at them, like we, military minds, know is wise and right!" (Does This Remind You of Anything?). It's a fleet parade day outside: itself a symbol of single-minded patriotism but alas, it would appear to be managed by those damn, bleeding-heart, no good pro-peace people. "They're having a parade while the evil, dangerous SDF are preparing for war!", cries the narrative. "Won't anyone stop the madness?"
Then, as if on cue as if to show the viewer that "this is the logical sequence of events" (peaceniks refuse to take military actions -> SDF causes catastrophic damage) the SDF attacks. It does so with overwhelming force, of course the enemy is dangerous and overpowering (so that if nay, when we defeat it it would be because we were genuinely better than them, not because we happened to have the stronger guns. Propaganda 101), and attention is instantly drawn to them attacking civilians and bombing residential areas for no apparent reasons. This, mind you, is all the while the UNSA fleet is literally parked nearby. According to the propagandist, the SDF is led by people so senselessly evil that they'd rather attack civilians for the heck of it than gain a military advantage. As the noble UNSA soldiers run and gun through the streets attempting to save the same civilians the SDF soldiers are executing (presumably while cackling insanely behind their facemasks), the narrative engages in an infamous propagandistic technique known as cognitive immunization: it presents weak arguments "for the opposite side" only to break them down in front of the viewer. Just like with injecting someone with a weakened pathogen, cognitive immunization presents little risk of the audience actually deciding to side with whoever the propaganda is directed against all the while convincing them that they're dealing not with propaganda but with a reasonable, objective presentation of the situation (after all, would a propagandist present the opposite viewpoint?). The UNSA soldiers, once again showing that they are moral and intellectual characters, attempt to reason out the SDF's motivations. But alas, says the narrative: there is none. The SDF know perfectly well what they're doing. They revel in it. Their leaders are unquestionably immoral, their soldiers are willingly complicit and they simply relish the opportunity to cause damage.
The importance of the fact that SDF is only able to pull off the attack with the help of a mole within the UNSA military cannot be overstated. Like all good propaganda pieces, it is meant to nurture a sense of paranoia within the audience even as it drives them to unite out of nationalistic pride. "The enemy could be everywhere, or anyone", tells them the propagandist. "Even within our own military and government. Only through your actions could it be ensured that only the good guys win." Sympathy for the enemy, it goes without saying, will bring only disaster - because the enemy is honorless, treacherous and ungrateful.
Like in 1940s Germany, it is clear that the propagandist thought it necessary to present the "good guys" in their narrative in this case, the UNSA as underdogs. In fact, we are literally told that, word for word. This is done by disarming them of their biggest ships and strongest guns, leaving them, on first sight, in the nonexistent mercy of the enemy. "But have no fear!", says the propagandist to the viewer as the orchestra booms and heroic lighting frames the faces of the UNSA soldiers "with courage and goodness, they (we) will triumph!".
It follows from there, throughout the game, in an infinite amount of little details. The UNSA treats women, homosexuals, people of color and robots equally well but all SDF soldiers are presented as samey looking men of same unidentifiable ethnicity (a useful means of ensuring that no member of the audience feels alienated, uniting them all against a common enemy). UNSA soldiers have a sense of humor and comradery but even when the heroes infiltrate SDF ranks (with an ease implying that the SDF military is either poorly organized and/or composed of selfish people who can't even recognize their own supposed friends), all they ever seem to do is gloat evily to each other about how much good UNSA citizens they've butchered and spout radical slogans (naturally, the propagandist has no interest in humanizing the enemy: they need the audience to see it as an impersonal force of evil, which is morally right to destroy). Most damning of all, though, are the "quotes" and "factoids" provided whenever the hero dies a moment in which, the propagandist no doubt knew, the audience would be in shock that such a likeable figure has perished and thus most susceptible to influence (again, a tactic previously employed by Riefenstahl and Goebbels): presented in white over a black field, completely out of context, as if to paint them as abject truths to burn into the audience's mind, one and all are clear, simple statements painting a very obvious picture. All quotes from Kotch or other high-ranking SDF officials are heartless and violent. They call for the destruction of the audience's beloved UNSA, or glorify the SDF but not in a relatable way, which might (god forbid) cause the audience to identify with them but in a cruel, militaristic and dangerous one. Clearly, SDF leaders have no emotions except hatred for the UNSA. They have no admirable ambitions, no love for friends or family and no sense of patriotism. They want only to see the good people of the UNSA burn, because they are evil. All factoids paint a grim picture of the enemy: the audience is told that SDF males must join the military for 15 years on age 12 (in one fell stroke presenting the SDF as chauvinistic, militaristic, uneducated and heartless not to mention implying that they literally know nothing except war against the UNSA and that they would have no future besides it, subtly convincing the audience that it would be an act of mercy to kill them), that they employ brutal propaganda techniques (ironic though that might sound, it is a well-known facet of real world propaganda campaigns. Of course that all we, the good guys, do is educate our citizens! It's the enemy who brainwashes their own!), that their military policies are focused entirely on causing damage to civilian infrastructure and, perhaps most outrageously, that they only call themselves the Settlement Defense Force in order to garner sympathy (mind you, this is not presented as a quote, but as a fact). There is no end to the underhanded tactics they'll use. They are pathetic and irredeemable. There is no option except to destroy them before they destroy us.
In short, according to this theory, the game is, in fact, not a true recollection of events, but an in-universe propaganda piece. From the hints we've collected, it would seem to have been released during a time of political tension between the UNSA and SDF, against a background of attempted diplomacy by some factions of the government (the "pro-peace" faction). The piece was commissioned by the militaristic "pro-war" faction in order to convince an unseen audience presumably the UNSAs civilian population - of the necessity of military action against the SDF. It uses specifically selected actors to depict SDF characters: ones picked for their threatening appearance and unidentifiable ethnicity, probably enhanced by selective use of makeup (same as how Nazi propaganda would specifically select the ugliest and most stereotyopically Jewish looking actors to present "the common Jew"). Its messages couldn't be clearer: we are dealing with an enemy that cannot be reasoned with, because they are not as humane or as moral as we are. There will be no peace with them, because they have no desires beyond our own destruction. Nothing we could promise them could change that. If we do not act quickly and decisively, they will act on their hatred and move in to destroy us. Of course we would still triumph in the end after all, we are noble and powerful. But the damage would be catastrophic, and the only way to prevent it would be for YOU, the audience brave and patriotic citizens of the UNSA, to vote for the pro-war faction today! Don't let the peaceniks win! When you vote for peace you vote for the SDF.
The Ministry of Propaganda would've been proud.
It's significant that those values are easily identifiable, though. The SDF has an ideology that looks like a hodgepodge of those present in the world today. They're Nationalistic, in a sense. Although they don't seem to attach any value to ethnic or racial identity, there's a definite sense of supremacy over people born on Earth. Their society is intensely Communalistic, in that individuals are expected to conform very strongly to social norms. Those norms are Militaristic, to an extent that would put the Proud Warrior Race Guy to shame. There's also an air of Utilitarianism to their actions, but not in the sense of maximizing pleasure and minimizing pain. Instead, they seek to maximize their attainment of their other values. Ultimately, they even appear to hold to a twisted variation of the Ideal of Progress. They're not better because of their ancestry, they're better because they are the only human beings capable of setting out and molding the galaxy to the benefit of their society. Earthborn humans are weak, and have primitive social structures that cannot advance the species further. In a sense, all of their other values exist to serve this core principle.
A society doesn't go from Socrates to Jeremy Bentham overnight, so it wouldn't make sense for it to go from Bentham to Kyubey without some intermediary steps. The SDF is one possible path. Still recognizable (and close enough to Italian Fascism that the two could be considered cousins once removed), but well on its way to becoming totally alien. Society on Earth, unfortunately, seems likely to turn toward a similar sort of Militarism simply to survive. Whether any rudiment of modern society can survive unscathed is a difficult question.
In short, if Infinite Warfare 2 ever comes out, robots based on Ethan would be the most important asset against the SDF. The SDF may boast a big space fleet that can bombard anywhere on Earth, but in the mission where you assassinate SDF leaders, the player can listen in and find out that their strategy does involve a full invasion, meaning they intend to land and take hold of the planet. When that part of their plan happens, Earth would respond by releasing their robot armies onto the invading troops and possibly hijacking SDF vessels. A lot of Earthlings would be killed by the initial bombardment, but in the long-term the SDF will never be able to conquer Earth.