This isn't an argument I feel super enthusiastic about stepping into, because it gets the most annoying sort of people in your mentions eager to maliciously misrepresent what you say.
However, yeah, there are some pretty terrible readings of Union floating around. I'd invoke "media literacy" because think that a lot of this comes from people not really holistically engaging with the fictional future history of Lancer, but also from a sort of dogmatic purism that requires future societies to be flawless, else they're irredeemable.
It is important to note that ThirdComm is the direct descendant of two highly imperfect societies. FirstComm was formed as a response to the Three Great Traumas of discovering the Massif Vaults (and thus that they were the inheritors of a fallen world), the wars over the Massif Vaults, and the discovery of the lost colonies, all of which collectively showed humanity how close it had come to total extinction.
FirstComm decided that it had a responsibility to ensure that humanity never risked extinction again. It manifested this by trying to colonize every habitable planet it could find, pumping out ship after ship to seed the cosmos with as much human life as it possibly could. This led to problems when it encountered civilizations like the Karrakin Federation and the Aun, who had been carrying humanity's torch just fine by themselves, thank you very much.
SecComm was an Anthrochauvinist fascist state. The book defines it thusly:
We can see a lot of Anthrochauvinist historical romanticism in the mech naming schemes of Harrison Armory, SSC and IPS-N - the fact that Harrison Armory names its mechs after great military leaders of pre-Fall Earth history, IPS-N does the same with naval figures, and SSC uses the names of Earth animals. Even the GMS Everest is named for a mountain on Earth. It's very Cradle-centric.
Anthrochauvinism was, to be clear, largely just an excuse for colonialism and hegemony. Atrocities could easily be justified under by stating that whoever they're being committed against were a threat to the Continuance of Humanity - a term that SecComm got to define.
It's also at this point that we have to zoom in from broad sociopolitical points to address one very specific piece of history: the New Prosperity Agreement. This was signed to prevent the outbreak of a Second Union-Karrakin War, and mandated that the Karrakin Houses would maintain privileged levels of autonomy within Union, and that they would be granted colonial rights to the entire Dawnline Shore. This agreement, struck in 3007u, basically defines much of the current political situation today.
ThirdComm was a final and inevitable reaction to the atrocities, abuses and excesses of SecComm. The unspeakable horrors of Hercynia were the spark, but I need to stress how little Hercynia actually mattered in the larger Revolution - at the start of NRfaW, it's explicitly stated that almost nobody in the galaxy even knows where it is, let alone what happened there. The Revolution was a generalized response to SecComm's tyranny, with no single rallying cry.
The Revolution might also have failed entirely, but for a critical error by Harrison Armory: pissing off the Karrakin Trade Baronies. After getting kicked off Cradle, the Anthrochauvinist Party organised a fleet at Ras Shamra to try and retake Cradle. Simultaneously, however, they were attempting to secure protectorate agreements to steal worlds in the Dawnline Shore out from under the KTB. Putting these two together and making five, the KTB assumed that the fleet was pointed at Karrakis, and started the First Interest War.
The First Interest War initially favoured the KTB. They smashed the fleet above Ras Shamra and simultaneously conquered the moon of Creighton in the Dawnline Shore. However, they underestimated just how ruthless Harrison I was - he "retook" Creighton by relativistic bombardment, and then conquered four of the 12 worlds of the Dawnline Shore with mechanised chassis, a technology the KTB had not adopted and had no counter for.
To prevent further loss of life, Union was eventually forced to broker a peace agreement that saw Harrison I handing himself over to Union justice in return for Harrison Armory's continued sovereignty, and the KTB joining Union as a full member state.
So, with that historical context out of the way, let me get to the second part of this absurd essay I'm writing.
Third Committee Union isn't a civilization that arose from whole cloth. It's shaped by five thousand years of Union history, six thousand years of post-Fall history, and six thousand years of pre-Fall history before that. It is, ultimately, an extremely well-thought-out and well-worldbuilt fictional polity, in that all of its imperfections come from traceable root causes in its history.
Why does ThirdComm permit the abuses of the KTB? Because to stop them, it would likely have to go to war, and such a war would butcher billions. Worse, to do so, it would probably have to ally with Harrison Armory and make horrific concessions.
Why does ThirdComm permit the expansionism and cryptochauvinism of the Armory? Because to stop them, it would likely have to go to war, and such a war would butcher billions. Worse, to do so, it would probably have to ally with the KTB and make horrific concessions.
Nobody in CentComm likes that Harrison Armory are empire-building expansionists. Nobody in CentComm likes that the KTB has a hereditary nobility and enforces blockades against planets that rebel against it. The problem is that ThirdComm is, in historical terms, still relatively new. They've been around five hundred years, and compared to the 1600 years that SecComm was around and the 2800 years FirstComm existed for, that's not very much.
ThirdComm is attempting to decouple itself from the Cradle-first politics of its predecessor, and to amend the many, many atrocities committed in the name of Humanity. It is not easy to do any of these things. SecComm was defined almost entirely by the fact that if it didn't like what you were doing, it would send in the military as a first response. Every time ThirdComm chooses to do the same, its legitimacy erodes, because the mission of ThirdComm is to prove that diverse, vibrant and compassionate human civilization can exist without devolving into war and bloodshed. ThirdComm always tries diplomacy as a first response because if it doesn't, millions of people could die.
