So, he feels that the Nazi gangs in East Ukraine were engaging in ethnic cleansing against Russian speakers / Russian nationals that was more or less state sanctioned by the state showing they weren’t interested in doing anything about it. He fully believes Russia’s stated purpose in all this is to seize control of East Ukraine in order to stop the Nazis.
Imo, there’s clear enough evidence that there’s a Nazi problem in Ukraine. What isn’t clear to me is why that’s a reason for Russia to expand its territory (spoiler alert: it’s an excuse, obviously. Russia also has a Nazi problem, like a lot of other countries. The northern hemisphere is working through some shit ATM.)