I mean there is definitely a lot of nationalism there. I have family in Russia and acquaintances fighting in the Donbas, so I'm no stranger to the strange Russian phenomenon of ostensibly right wing nationalists that aren't anticommunist. It's not really as cut and dry as comfy western leftists make it out to be. When the government bans your language from being taught in schools or used in official business, and neonazi death squads commit acts of terrorism against people of your ethnic group, it's not surprising that nationalism grows. The cultural, historical and material conditions are so different there that viewing the situation from a western lens is pointless. Russian Nationalism in the Donbas is even different than Russian Nationalism in Russia. In Russia it often takes a chauvinistic form, while in the Donbas it's liberatory. For instance, there are majority ethnic Greek villages in the Donbas who have been subjected to hate crimes and terrorism by neonazi Ukrainians. These people are not ethnic Russians but they closely align with the Russian separatists because that's who protects them. It's like the IRA, some of them are socialists and some of them aren't, but they're inherently nationalistic and their cause is just.