There are quite a few points I'll have to disagree with. The matter of the EU association was not "democratically settled". Yes, there was an offer, but among the EU demands was the acceptance of an IMF program that would among other things have stopped gas subsidies. Together with a loss of their primary market - you remember the Brexit primary color slides about being part of exactly one trade block? - it would have led to a massive jump in poverty and the end of eastern Ukraine's heavy industry. Yanukovich's electoral base would have suffered grievously. Of course the country was split about that, you can see the East - West divide on all election maps but the Russian offer was just objectively better at that point.

You claim Ukraine was de-facto under Russian control, but I really don't see how that is a fair characterization. After the fall of the USSR you have the successor regimes that are more or less run as extraction colonies by Western institutions, Russia certainly wasn't in any position to impose anything on its neighbors. Even after Russia stabilized the big change in the political system in Ukraine was the orange boys and girls taking over, that's hardly Russia running the country, is it? Of course after they didn't deliver and fell out among themselves the Eastern based Yanukovich came to lead the country. What's the timeline of "de-facto" Russian control you propose? Between the election of Yanukovich and Maidan? The mythical 300 years of oppression the sons of Bandera in Canada like to imagine?

Of course we have no proof whether the Donbas militias were cooked up in some Kremlin plot, but the material basis was there and the Russians hardly were expecting Maidan. Why would the people of Donbas accept the new government that replaced the one they voted inoverwhelmingly? The one that very publicly wanted to clean Ukraine of their language? That banned the communist party that still had a decent presence in the East?
You bring up the American civil war, though what is it supposed to tell me with the moral content stripped out? The Donbas militias aren't fighting for chattel slavery.