In a way, it's somewhat comparable, since the state I live in used to belong to a Spanish-speaking country. (Before that, it used to belong to people speaking Apache, Tohono O'odham, and Navajo, among other languages.)
That's also been a contentious issue for them, as during the Tsarist period, there was a concerted effort towards Russification of the non-Russian nationalities. When the Bolsheviks took power, they initially opposed Russification and wanted to encourage multinationalism and allowed Republics to adopt and use their own language (with Russian being the overriding lingua franca of the USSR). When I was in Soviet Georgia in the 1980s, I saw bilingual signs in both Russian and Georgian (which uses a completely different alphabet).
It seems that South Tyrol was used as a bargaining chip to encourage the Italians to join the war on the side of the Allies in WW1. Apparently, Hitler and Mussolini reached an understanding that would have allowed for Germans to return to Germany if they so desired. (
South Tyrol - Wikipedia)
After WW2, the Allies were in a position where they could have redrawn the borders and put South Tyrol back in Austrian hands, but they chose not to do that.
Whether mandated to do so or not, it does make sense for someone living in a country to speak the predominant language of that country. They were living in Ukraine, so learning Ukrainian seems a sensible thing to do. Just like a German living in South Tyrol; they may not be forced to learn Italian, but it seems like it would be a good idea just the same.
I get a strong sense that people in the non-Russian former Soviet Republics have a longstanding grudge and resentment against Russians in general. They see Russia as a former oppressor and themselves as victims of Russian oppression. It could be analogous to how Latin Americans see Anglo Americans as "Yankee Imperialists." While it's perfectly understandable that they would be resentful over past oppression, I can also understand how it must be for those who are innocent, yet attacked or hated merely because they share the ethnicity or race of a former oppressor.
I think I've told this story before, about how some Americans traveling in the USSR were in Lithuania, and asked for directions (in Russian) of a passer by, a Lithuanian who gave them the cold shoulder because he thought they were Russians. As he was walking away, he could hear them speaking English, so he came back to them and was quite friendly and accommodating. The guy clearly didn't like Russians, and I have no doubt that such scenes have occurred throughout the former Soviet Union by people who simply didn't like Russians.
The irony of that is that even the Russians didn't seem to identify with "Soviet" all that much in practice. Stalin was actually Georgian, not Russian, which makes their grudge against "Russians" all the more curious and inexplicable. I don't see that they would be analogous to say, the British in India or the French in Algeria or Jim Crow in the Southern U.S. It wasn't like that, since all races and nationalities were considered equal under the Soviet Constitution. I realize it didn't always operate that way in practice, but still, officially, they saw Communism as truly internationalist and open to oppressed peoples of all races and nationalities.