I lived in a small town during the Soviet era and never saw anyone with dark skin there. When a mulatto girl (her father was Cuban) came to our school, all the kids looked at her as if she were a miracle. No one would have thought of insulting her. I remember we were raised to respect all nations of the Earth.
That's a lovely way to grow up. I never remembered racism either but then I wasn't subject to it and just because I didn't see it didn't mean it didn't exist.