That’s what the Ukraine has been doing to Crimea?
Yikes. You just don’t DO that to the Bear.
The Russians starved millions of Ukrainians to death. Khrushchev was the Butcher of Ukraine. After WWII, the Red Army slaughtered hundreds of thousands of civilians while putting down a Ukrainian insurrection led by Stepan Bandera. That's the background for Khrushchev's "gift" of the Crimea to Ukraine. It was a peace offering, a consolation prize. I have no idea how emotive this issue is to Ukrainians, but given that Russia has never offered reparations of any kind other than the territorial one, it may be more significant than anyone thinks, and significant enough that Ukrainians are willing to die (and kill Russian troops) in large numbers to keep. Ukrainians are descended from the Cossacks whom the Russians have repeatedly massacred in large numbers in order to keep Ukraine within the Russian empire. In a way, Ukrainians share a history with the Poles of repeated large-scale insurrections against Russia, but without successfully holding the Russians off long enough to regain their independence.