The world we live in is populated by imperfect people. That's why we helped Russians hold off the Germans by supplying them and opening a second front in North Africa, Southern Europe and then Western Europe. Both were responsible for the deaths of tens of millions but we ended up backing the lesser of two evils, despite the Russian record of genocide under both the Bolsheviks and the Romanovs. The KLA, the Syrian rebels and the Ukrainian right aren't angels, but neither are their adversaries. Even if you add all of the deaths on both sides in the conflicts they fought, the total doesn't hold a candle to the bloodshed inflicted by Russia on the world.
In the Ukrainian context, it's obvious that Ukraine is a less-developed country with no ambition or chance of ever conquering the world. Russia is precisely the kind of world-conquering power that needs to have its territorial goals kept in check before it acquires enough population and resources to become unstoppable.
Russia is acting the thug, no doubt, but given that we have been told ad nauseum by GOP keaders, people on Fox News, Democrats, Kerry and Obama, too, that the U.S. is the last remaining superpower, it could easily be said that Russia cannot conquer the world, much less most of Eurasia.
Sure, they could cause a major mess, but I doubt that it would extend beyond Eastern Europe, and were they to even do that, a complete isolation of them in regards to oil, banking, commerce, etc, would destroy their stock market and the Russian oligarchs in and outside of Russia would remove Putin fast.