In fact, if the US can interfere in a country that's thousands miles away by funding extremist military groups, I find it way more legitimate for Russia to fund Russian separatists in the Donbas region, which has historically had strong ties with Russia and whose population would rather stay there than join the "Western" side. It's also interesting how everybody always talks about self-determination, but only in the case where people want to "self-determine" themselves in the right direction. I would be interested in knowing why it doesn't apply in this case.
To conclude: the Ukrainian army along with this these neo-Nazi groups (that have been effectively integrated into the army) has destroyed several hospitals, schools and other civilian infrastructure and killed more than 3000 civilians since 2014 in the Donbas. Ignoring this situation and blaming everything on Russia is one of the reason that we are in this situation right now, and surely one very myopic way of assessing what's going on.