Your take on Odessa is wrong on so many levels. For starters, the total number of people who died there was 45, not 300, and most of them weren't ethnic Russians, but rather locals (who are mostly Ukrainians, even if many of them are Russophone) who supported Yanukovich. Neither did it happen out of the blue - it was preceded by street fights involving firearms (and some of people carrying those firearms were later in the Trade Union House), said fights triggered by an attack by a pro-Yanukovich mob on an anti-Yanukovich protest.

https://en.wikipedia.org/wiki/2014_Odesa_clashes#Events