Those ethnic relocations (not deportations) were entirely about WWII. Many of them were on the side of the Nazis. They were done to move them physically away from Nazi influence and away from the war theater. Each was moved together as a group to preserve their ethnic relationships. The USSR could have dispersed them as a diaspora or expelled them, were ethnic cleansing their goal. These were drastic measures to be sure, but they were done because of the existential threat of the Nazi terror and not for any other reason.

The anti-cosmopolitan campagne.

That wasn’t an ethic minority issue. Unless you want to argue that is was antisemitic, which would be silly given how many in high positions of the Party and the government were Jewish.

Various crimes against humanity during the great purge.

That wasn’t an ethnic minority issue, either. That was a counterinsurgency against bourgeois counterrevolution. It was to preserve the socialist gains they’d won a generation before. A (long) excerpt from Michael Parenti’s Blackshirts and Reds: Anticommunism & Wonderland

Here’s a snippet:

The pure socialists’ ideological anticipations remain untainted by existing practice. They do not explain how the manifold functions of a revolutionary society would be organized, how external attack and internal sabotage would be thwarted, how bureaucracy would be avoided, scarce resources allocated, policy differences settled, priorities set, and production and distribution conducted. Instead, they offer vague statements about how the workers themselves will directly own and control the means of production and will arrive at their own solutions through creative struggle. No surprise then that the pure socialists support every revolution except the ones that succeed.

The pure socialists had a vision of a new society that would create and be created by new people, a society so transformed in its fundaments as to leave little opportunity for wrongful acts, corruption, and criminal abuses of state power. There would be no bureaucracy or self-interested coteries, no ruthless conflicts or hurtful decisions. When the reality proves different and more difficult, some on the Left proceed to condemn the real thing and announce that they “feel betrayed” by this or that revolution.

The pure socialists see socialism as an ideal that was tarnished by communist venality, duplicity, and power cravings. The pure socialists oppose the Soviet model but offer little evidence to demonstrate that other paths could have been taken, that other models of socialism — not created from one’s imagination but developed through actual historical experience — could have taken hold and worked better. Was an open, pluralistic, democratic socialism actually possible at this historic juncture? The historical evidence would suggest it was not. As the political philosopher Carl Shames argued:

How do [the left critics] know that the fundamental problem was the “nature” of the ruling [revolutionary] parties rather than, say, the global concentration of capital that is destroying all independent economies and putting an end to national sovereignty everywhere? And to the extent that it was, where did this “nature” come from? Was this “nature” disembodied, disconnected from the fabric of the society itself, from the social relations impacting on it? … Thousands of examples could be found in which the centralization of power was a necessary choice in securing and protecting socialist relations. In my observation [of existing communist societies], the positive of “socialism” and the negative of “bureaucracy, authoritarianism and tyranny” interpenetrated in virtually every sphere of life.

The pure socialists regularly blame the Left itself for every defeat it suffers. Their second-guessing is endless. So we hear that revolutionary struggles fail because their leaders wait too long or act too soon, are too timid or too impulsive, too stubborn or too easily swayed. We hear that revolutionary leaders are compromising or adventuristic, bureaucratic or opportunistic, rigidly organized or insufficiently organized, undemocratic or failing to provide strong leadership. But always the leaders fail because they do not put their trust in the “direct actions” of the workers, who apparently would withstand and overcome every adversity if only given the kind of leadership available from the left critic’s own groupuscule. Unfortunately, the critics seem unable to apply their own leadership genius to producing a successful revolutionary movement in their own country.

Tony Febbo questioned this blame-the-leadership syndrome of the pure socialists:

It occurs to me that when people as smart, different, dedicated and heroic as Lenin, Mao, Fidel Castro, Daniel Ortega, Ho Chi Minh and Robert Mugabe — and the millions of heroic people who followed and fought with them — all end up more or less in the same place, then something bigger is at work than who made what decision at what meeting. Or even what size houses they went home to after the meeting. …

These leaders weren’t in a vacuum. They were in a whirlwind. And the suction, the force, the power that was twirling them around has spun and left this globe mangled for more than 900 years. And to blame this or that theory or this or that leader is a simple-minded substitute for the kind of analysis that Marxists [should make].

To be sure, the pure socialists are not entirely without specific agendas for building the revolution. After the Sandinistas overthrew the Somoza dictatorship in Nicaragua, an ultra-left group in that country called for direct worker ownership of the factories. The armed workers would take control of production without benefit of managers, state planners, bureaucrats, or a formal military. While undeniably appealing, this worker syndicalism denies the necessities of state power. Under such an arrangement, the Nicaraguan revolution would not have lasted two months against the U.S.-sponsored counterrevolution that savaged the country. It would have been unable to mobilize enough resources to field an army, take security measures, or build and coordinate economic programs and human services on a national scale.

For a people’s revolution to survive, it must seize state power and use it to (a) break the stranglehold exercised by the owning class over the society’s institutions and resources, and (b) withstand the reactionary counterattack that is sure to come. The internal and external dangers a revolution faces necessitate a centralized state power that is not particularly to anyone’s liking, not in Soviet Russia in 1917, nor in Sandinista Nicaragua in 1980.

Engels offers an apposite account of an uprising in Spain in 1872 in which anarchists seized power in municipalities across the country. At first, the situation looked promising. The king had abdicated and the bourgeois government could muster but a few thousand ill-trained troops. Yet this ragtag force prevailed because it faced a thoroughly parochialized rebellion. “Each town proclaimed itself as a sovereign canton and set up a revolutionary committee (junta);” Engels writes. “[E]ach town acted on its own, declaring that the important thing was not cooperation with other towns but separation from them, thus precluding any possibility of a combined attack [against bourgeois forces].” It was “the fragmentation and isolation of the revolutionary forces which enabled the government troops to smash one revolt after the other.”

Decentralized parochial autonomy is the graveyard of insurgency — which may be one reason why there has never been a successful anarcho-syndicalist revolution. Ideally, it would be a fine thing to have only local, self-directed, worker participation, with minimal bureaucracy, police, and military. This probably would be the development of socialism, were socialism ever allowed to develop unhindered by counterrevolutionary subversion and attack.

One might recall how, in 1918-20, fourteen capitalist nations, including the United States, invaded Soviet Russia in a bloody but unsuccessful attempt to overthrow the revolutionary Bolshevik government. The years of foreign invasion and civil war did much to intensify the Bolsheviks’ siege psychology with its commitment to lockstep party unity and a repressive security apparatus.