For just about all former soviet states, the N word is the term used to describe black people, because the word imported from Europe to describe Africans. It doesn’t have the connotations or baggage that westerners attach to it. Diddo for blackface and sambo imagery, it’s usually used more out of ignorance than malice.
Oh dear God, let me tell you, I feel my bones tickling when I read this. All these flashbacks of my parents meeting other Russian people and, all of the sudden, casually dropping the n word in conversations in public and me just freezing and praying no one overheard them. I mean it was with no mean intent (as you wrote, more like ignorance paired with custom) but if someone heard them, then they didn’t understand the context and only heard them say n*ger.