There is a difference between ethnicity and citizenship/nationality. Back in the USA, if someone asked me what I was then I would say I'm Mexican. But that doesn't mean I have Mexican citizenship. It just means that my family background is Mexican (and a little German). If someone in Europe asks me what I am then I have to say American. If I say Mexican then they assume that I have a Mexican passport. And over here, saying Mexican-American just really confuses folks.In Europe, everyone goes by citizenship. If your parents were Hungarian but you have a German passport then here you are German.
I guess it's just another one of those cultural differences between the USA and Europe. In the USA, you could have someone say that he is French. Even though he can't speak French, has never been to France, and the last person in his family to come from France was his great, great, great grandfather. But that's OK, he's still French. Or rather, his family background is French.
A big issue I've seen here is the Hungarian minority in Slovakia. Are they Slovaks? Are they Hungarians? You don't always get a clear answer.
Even though my family background is Mexican, I'm an American. I served in the U.S. military. I was born a U.S. citizen, as were my parents, and I have a U.S. passport. It doesn't say anywhere on my passport that that I'm ethnically Mexican. All my passport shows is that my place of birth was California, USA.
Maybe it's because the USA was built on immigration. Or maybe because there are so many countries in Europe that it is just easier to stick to citizenship.
I did find out one little interesting thing that happened when Czechoslovakia split up during the Velvet Divorce. All Czechoslovakian citizens had to choose if they would now be Czech or Slovak. I'm sure that geography played a big part in helping people choose. But what happened if you were originally from Bratislava but had moved to Prague? Would you switch from Slovak to Czech so that you could be a citizen of where you now lived? And what about mixed marriages? If your mom is Czech and your dad is Slovak, did the two countries allow the kids to have dual citizenship? Hopefully someone can share some insight on how it all worked.