Doesn't matter that half the people didn't voted at all.
What happened to all those Banderos and other Nazi/nationalist extremists that the Russians were so deeply concerned about? Willy Wonka intimidated them into staying at home?
I have a better theory that makes more sense: a small minority of Russian nationalists and Russian football hooligans were making most of the trouble, putting on a nice show for the Russian media about "those crazy Ukrainians".