You mean when the democratically elected parliament removed Yanukovych from office after he conspired with the Russians and then fled the country? Even if it were as you have characterized it, it would have been no threat to Russia. You also conveniently ignore the fact that there were two (2) national elections afterwards and that the present government was freely elected, not "installed."
Neither was waging war on disenfranchised voters who wanted to secede in Donetsk and Luhansk.
They were not disenfranchised. They could have freely participated in the following two elections if it were not for the Russian military occupation. Nor did the populations there, which are majority Ukrainian, seek to secede. Even in the Russian controlled "referenda" the vote was only for autonomy in a united Ukraine.
A parliament that had over a hundred members absent, and that could not register an actual impeachment of Yanukovich because they lacked the necessary number of votes to do so.
I mean, I'm sure a unanimous vote to remove Yanukovich had *nothing* to do with the fact that Euromaidan protestors in Kiev numbered in the tens of thousands, had gained de facto control of numerous administrative buildings, and had already signalled their dissatisfaction with the February 21 compromise deal (via vocal boos and official communications from Right Sector). The threat of getting swarmed by an unhappy mob had no impact on the Rada's decision (much less those who decided to skip town entirely), surely. /s
They could have freely participated in the following two elections if it were not for the Russian military occupation.
When the political entities that previously represented the majority of your interests get undemocratically ousted, I'm sure the prospect of voting becomes less appealing.