They had never met a black person in real life.
Your culture is different than theirs.
Wolfram-Alpha agrees: they will likely never have met a black person. http://www.wolframalpha.com/input/?i=black+people+in+ukraine
On the other side of the coin, while visiting Dallas on work from Europe, I was asked, quite seriously, whether I was worried about the the Muslim campaign to control Europe by outbreeding the natives (or something, I'm not good at remembering this stuff). I don't think they'd ever met a Muslim in their life.
And yeah. What a world we live in. Hopefully someday these people will find out how perfectly usual everyone is, even people from different cultures.
So their only impression of what African Americans are really like is presumably formed via American media?
Hmmm....