They knew they couldn't win the upcoming elections so they overthrew the government.
Yanukovich was polling lower than the nationalist Tyahnibok. Notice how Donbas cause today is not for Yanukovich but for federalization, separation, Russia, etc. Only way he would win the next election was if Ukraine was turned into Russia/Belarus (which he tried to do with his January dictator laws) but then...
The civilians are Ukrainian.
The Maidan crowd claim to be the government of the Ukraine.
The present government of the Ukraine has command the Ukrainian Army to kill Ukrainians.
If it's tough dealing with these alleged Specnaz then the SOBs that overthrew the government prefer murdering of civilians to tough decisions.
Straight forward, PERIOD.