The best counterpoint for most westerners to understand is this: most Irish people speak English as their primary, if not only, language. Yet English-speaking Irishmen were (and still are) vehemently against being part of the UK.
I'd even say Ukraine is probably more like California, (or Texas) in relation to US, rather than Ireland in relation to GB. And just like I wouldn't mind if California separated from US, I don't mind Ukraine being separate from Russia, but the cultural ties are probably similar to the ties between CA and the rest of US.
> it was happy to be part of Russia/USSR
It was so happy in Imperial Russia that the authorities saw it fit to severely censor publications in Ukrainian:
https://en.wikipedia.org/wiki/Ems_Ukaz
It can also be instructive to look at this list and see how many of those were against Russia.
https://en.wikipedia.org/wiki/Cossack_uprisings
As for the USSR, well, there was that whole Holodomor thing.
Nationalists are usually the loudest minority, while the bulk of population does not really care.
Shortly after, Germans rolled in and devastated the country. Then, the Russians came back through, treating everyone still alive as a Nazi collaborator (because "how could they still be alive, if not?"). Ukrainians who had been drafted by the Nazis and forced to serve as cannon fodder, but survived, were shot or deported to the GULag as traitors (because "how could they still be alive, if not?").
Ukrainians do not think of themselves as Russian even so much as Irishmen consider themselves English.
Culture is really hard to pin down, and there are examples of distinct national identities that are really hard to differentiate in ethnographic terms--the US and Canada are the example that comes readily to mind here.
As for the "Ukrainians happily being part of Russia/USSR" bit, I think the sibling comment does it more justice than I can.
All of the Ukrainian imigrants in North America would dispute that. See also, Holodomor.
As for Holodomor, it was caused by a bloody dictator who killed a lot more Russians than Ukrainians during the same period, so I'm not sure it proves anything about Russian/Ukrainian relationship. To him it would not make any difference if Ukraine was not part of Soviet Union (see how he treated Poland).
