It's weird how Russians simultaneously gloat about being progressive non-racists & openly loathe multiracialism & racial admixing.
It really is not.
You have to consider that Russia is not a nation-state. It is the Russian
Federation, with many ethnicities and cultures who are not ethnically Russian.
You could compare it to Habsburg Austria, one central nationality, the German-Austrians in the west, ruling/cooperating with the other ethnicities and cultures of the Empire.
If Russia would accept ethnic nationalism, they would have to accept that the other peoples, like the chechens, would maybe want their own nation states, not being ruled over by Russians forever.
HOWEVER, this is very different from the western (doomed to failure) multicultural, mass-immigration system.
Every one of the Federated nations in Russia have their own territory, and some rate of local independence. This is very different to, for example Germany importing millions of Turks or Arabs, who build their own seperate ghettos all over the country, in every city. You could very easily split up Russia along ethnic lines, like was done with Austria, but how would you do that in the German example?
They don't want Africans, because they are not a nation in the Russian federation. They don't want mass immigration. They want to preserve their
cultures. Not just the Russian culture, but the ones of the federated Nations too.
