because it has been made clear by Crimea and Donbass that if Ukraine tries it openly, the Russian tanks will come to Kiev, and Ukraine will lose even more territory. The massive shelling of cities, mainly and primarily Donetsk, by the Ukrainian forces (in many cases using cluster warheads on unguided missiles fired from multiple rocket launcher systems like "Smerch" and "Uragan" into the purely residential high-density districts located far from the actual battle lines) is the genocide and ethnic cleansing being performed under the cover of military action.
>Let's try another one: how many people in eastern Donbass would have died if Girkin and his people hadn't appeared in Slavyansk prompting a covert military invasion from Russia? (hint: consider the rest of Donbass and the South-East of Ukraine).
Girkin provided the focus point for the nationalists forces who had been doing "buses and trains of friendship" across all those regions and thus his incursion stopped the escalation of violence in those regions. It was like a lightning rod taking the hit away from other places. The message was clear - you either continue beating up and burning pro-Russian protesters in Kharkov, Odessa, etc... while Girkin takes the territory or you come and fight the Girkin thus leaving other people alone until Girkin problem is solved. As i was saying back at the time - until Ukraine understands that violence and oppression wouldn't provide the solution, Ukraine will be losing the territories and losing in other domains too.