I think it’s important to understand that Marxist-Leninists should be supporting the people of both countries, rather than picking one of two capitalist states to back. I understand that Russia has its excuses for doing this, and the Ukraine government has its excuses for what it has done, but it’s important to remember that they are both capitalist countries in the age of imperialism; what they are really after is power. Please feel free to correct me if you believe I got anything wrong.
Russia, in its rivalry with West, is doomed to help oppressed states like Syria, CAR, now Donbass. Not sure they doing it because of sympathy to oppressed people, but I think it deserves critical support anyway.