The Russkies killed around 7 million Ukrainians in the Holodomor-- rivaling the holocaust, and we turned a blind eye to it then too.
Not to worry. The Budapest Memorandum assured Ukraine that getting rid of their nuclear weapons (which were under Russian operations control) was the best move and the US and Brittan would have their backs in the event of trouble. It was agreed to by the Russians too so no need to worry /sarcasm