It is so bizarre to me how he consistently and entirely disregards the idea of Ukraine's sovereignty and right to self-determine. Imperialism as inherently justified seems to be a foregone conclusion. If they want to join NATO, or do anything else, Russia does not have the right (not desire) to invade to prevent it, which seems to be his entire thesis. His correlation to a pro Russo-China Canada seems absurd to me because he assumes the US would invade Canada in a similar way but with wide support from The West. I do not agree.

I didn't get the impression that the author believes that Russia had "a right" to invade Ukraine. You're conflating attempts of understanding a behavior with attempts of justifying it. These are two very different things.