Your problem is with international law which respects the territorial sovereignty of nations and does not recognize a right of sucession by a group unless their right of internal self determination is compromised. In this case the Ukrainian constitution requires a referendum of all Ukrainian people

So when rightists oppose secession because, while they hate the ethnic Russians who want to leave, they don't want those ethnic Russians taking the land, etc. with them, we should be moved by this motivation and not consider the right of self-determination compromised?