I see that! I think Eastern Europe is one of the regions of the world Americans know the least about. It's like it's just the UK, France, Spain, Germany, abunchofstuffinthemiddle and then Russia! What's in the middle? No one knows!
And then, when someone plays someone from there in a show, it's usually some caricature played by an actor who's done equally unrealistic characters of other ethnicities before.
But people don't care, 'cause Eastern Europeans are Europeans, and Europeans are white, and white people don't have cultures, right?? /s/
To be honest, though, American portrayals of other Europeans aren't all that great either. French people are all finicky, snobby weirdos and the British are delicate and humorless and they've all met the Queen before. And don't get me started on German stereotypes...