I’m sure Russia has operatives in Ukraine, but as the article states, clearly most of these people are disgruntled locals. 48% of the voters voted for Yanukovych in the last election. Many of them won’t accept that their candidate was chased out of office in a coup, just like many people in America wouldn’t.
There was no coup. The interim government in Ukraine is the Ukrainian Rada that was democratically elected in 2012. Yanukovych did not run on a Pro-annexation, Anti-EU platform, and his party turned on him. 65 to 75 percent in multiple polls in the East and South show an overwhelming majority oppose annexation and separatism, including polls taken as recently as this month.