How did they end up like this, anyhow? It's weird to think there isn't more animosity towards the guys who shot at their great-great-granddads or whatever.
My basic understanding of it is if you think both capitalism and communism failed, there is one ideology left to try, and these people have been indoctrinated with "communism bad and doesn't work" for the last 30 years. The collapse of the Soviet Union would be a sign to the uneducated and/or propagandized that communism doesn't work, and the last 30 years of Ukrainian history have made it clear that capitalism doesn't work. Depressed civilians then turn to the last major ideology that is coincidentally being propped up by both national and international interests, and you have the absolute disgrace that is Nazism and fascism in Ukraine today.
There was a non insignificant segment of the Ukrainian population that sided with the Nazis when they invaded (UPA, OUN-B), mostly in the western part of the country). These guys very much enjoyed a good war crime against Poles, Jews or Russians, enough that they were willing to ignore the Germans killing other millions of other Ukrainians, most of whom did heroically defend their homeland alongside the Red Army.
After nazis lost, Stalin annihilated these bandit groups. He and Beria were extremely thorough in laying waste to the collaborators. However in the years since the fall of the Soviet Union the more nationalist/nazi-adjacent side of the Ukrainian government is continuing the tradition of their nazi collaborating ancestors and turning the OUN-B into the patriotic martyrs.
I think expat communities have something to do with it. I was listening to a podcast about modern reactionaries and nazis the other day, and they did an episode about Slavic Native Faith. The Ukrainian brand was started by a Ukrainian, but took off in the States long before it gained a foothold in the motherland.