I think it is Russia's fault that such horrible things happened in Ukraine. First of all, Crimea belonged to Ukraine. It was officially part of Ukraine. Second of all, Ukrainian people weren't able to have a peaceful protest. They wanted Yanukovych to sign the EU Pact, which he refused to do. Then Putin brought his own militia, and hundreds of innocent people were killed! They were tortured in front of everyone, with no one to defend them. The important thing is that they didn't give up, and fought until the end. Russia hands of Ukraine!!! Do you think that the U.S should take a stronger stand in this matter?
Ukraine's situation is due to the fault of American imperialism. As we know, at the end of the Cold War, the Soviet Union broke apart leaving the United States as the sole hegemony. Soon after, the United States made promises to Russia to not expand N.A.T.O into the Former Soviet Republics. 20 years later, the only states not in N.A.T.O are Belarus, Ukraine, and Moldova. The Americans are choking them in the geopolitical realm.
Imagine if the U.S lost the cold war, and Russia promised not to influence the Western hemisphere, 20 years later, Mexico and Canada are left in America's influence. Then Imagine Russia meddling into Canadian affairs. What would the U.S.A do? They would intervene, the U.S would feel like they are being choked.
There was a leaked phone call between two European nations explaining how they "believe" the snipers used during the protests were funded by the protest leaders. After the protest leaders gained power, they refused to look into the matter more deeply. Now, assuming they are right, the protest leaders would need money to finance these said snipers. Thus, the protest leaders need funding. Who would fund them? Russia sure wouldn't, the last thing they want is the protesters to get angry and topple the government, thus who do you think would want to anger the protester to partake in these actions?
My guess says the American government who for decades now have wanted to wrestle Ukraine away from Russian influence.