After having talked about the balkanization trope based on dividing the country by force in a war, I am going to talk about the trope that for lack of another name I have called “The evil separatist”.
In principle, we might think that this trope is not very different from the previous one: that is, a territory declares its independence from a larger country by force of arms, and immediately initiates “special military operations” to “stop an aggressor hostile” (referring to the country from which they are separating). At the same time, he almost immediately begins the forced expulsion of "minorities who only know how to hate" to "protect us from the threat posed by this fifth column of hostile populations." Any atrocities they commit will be framed as "legitimate self-defense against an evil oppressor who seeks our destruction as a people."
The only significant difference, at least in theory, is that this territory, instead of being supported and supported by a hostile invader who is tearing the big country apart, has become independent by its own means and initiative.
In principle, and in theory, this should translate into this country receiving the same sympathetic treatment as its “independent” counterparts: being portrayed as innocent and poor victims of the unrestrained brutality of the country they are freeing themselves from, right?
Well no, it is not like that.
This independent territory will be systematically portrayed, both outside and inside the TL, as a terrorist entity in rebellion. A dictatorial and tyrannical regime, made up of people who only know how to hate and who became independent solely and exclusively because of their racist and insane hatred. A group of thugs that pretends to be a government, that is absolutely not legitimate, and that obviously deserves to receive the most cruel and ruthless treatment by the authorities of the big country. Regardless of how badly they were treated by the authorities of the big country, it will be systematically assumed that they have no legitimate reason to rebel, and that they are actually traitors who hate the country.
Of course, no one will see the slightest contradiction between advocating at the same time “these people hate this country and we'd actually be a hell of a lot better off if they just walked away and left us alone” and “nothing is more just and good than forcing these people, whom we detest anyway, to remain a part of our country even if it means waging a civil war to keep the country united by force.” Any war crime, no matter how heinous, automatically and immediately becomes "strict justice and karmic retribution" if it is perpetrated against this entity and its inhabitants.
This is seen most notably in the American Civil War TLs, when the "Nazi States of America", led by a grouping of all the crazy right-wingers in America, proclaim their independence and immediately begin the extermination of all non-whites.
In addition to this, the "Nazi States of America" (or whatever the country in question is called) will act in a way that, in addition to including all acts that are previously celebrated as "necessary to guarantee the security of this nation", will add others who seem more destined to attract upon themselves the hatred of the entire rest of the planet, and make it clear to the rest of the world that there is no one who is more vile and evil than they (and that, therefore, nothing is more good and fair than supporting the Federal Government), than based on some kind of plan.
Expect from them things like invading neighbors, deploying nuclear weapons (if they have them) against rebellious cities, opening death camps, and immediately implementing whatever Nazi policies they can emulate.
It may be objected that this type of regime seen in the American Civil Wars actually IS evil, and no one will argue with it. But the problem here is that this "This is an evil regime that must be stopped" treatment is received even by separatists who aren't trying to be cartoonishly evil.
Unless, of course, they are from ethnicities that "fall in sympathy": the Islamic Caliphate of Kurdistan starting a systematic genocide of the Turks as part of their efforts to gain independence from Turkey is all very well, but the Lakota Nation declaring independence from The United States is a strategic threat that deserves to be repressed with the full force of the American military.