Anything which is not ethnic Russian in Russia is black. And there is lots of racism in Russia everywhere, open racism, where even police doesn't help and in fact encourages racism subtly.

Because they have black hair, dark eyes and usually darker skin shade. So it's rather logical.

Simply because they have dark hair and dark skin...so they are not white like the Russians. So it makes sense really.

Do you have anything against black hair and dark eyes?

Because, if compare them with russes, they are black.