You don't know what the truth is there, you cannot rule out the protests were getting out of hand and protesters started to be aggressive towards police.
Who knows what triggered it.
http://news.howzit.msn.com/news-in-pics/ukraine-mourns-protest-deaths-28
Look at those pictures and tell me that 40-50 yearold woman in center "triggered" it by being aggressive. Or the man holding his cat. Take your head out of rear end and open your eyes. Those people were massacred in the streets, in Europe, in the 21st century! There's no excuse for it, none, zero, NADA.